9 - Lifestyle Interventions for Patients with Diabetes
Authors: Unger, Jeff
Title: Diabetes Management in the Primary Care Setting, 1st Edition
Copyright 2007 Lippincott Williams & Wilkins
> Table of Contents > 9 - Lifestyle Interventions for Patients with Diabetes
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9
Lifestyle Interventions for Patients with Diabetes
Take Home Points
Primary care physicians (PCPs) should take the time to educate their patients with diabetes on issues related to medical nutrition therapy, exercise, weight reduction, and long distance travel.
Patients who are noncompliant make a willful attempt to disregard the physician's treatment plan. Patients who are nonadherent are fully informed about their individualized treatment plan by the physician yet decide to pursue other options on their own. Improving adherence can reduce diabetes complications.
Reducing caloric consumption by 150 cal per day can result in a weight loss of 1 pound per month.
Whereas patients with type 1 diabetes mellitus (T1DM) must dose their insulin based on the meal's carbohydrate content, patients with type 2 diabetes mellitus (T2DM) should strive to follow the recommendations as set forth by the diabetes food pyramid.
Exercising at moderate intensity 5 days a week can improve hemoglobin hemoglobin A1C levels by 0.6% in patients with T2DM.
Patients with T1DM who exercise should receive specific pre-exercise safety instructions.
Pre-exercise cardiovascular screening is appropriate for many, but not all, patients with diabetes.
Traveling with diabetes can pose logistical challenges for patients.
Proper self blood glucose monitoring can offer valuable insight on diabetes management.
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Case 1
Forty-nine-year-old Brett is very despondent about being diagnosed in the emergency department (ED) yesterday with new onset type 2 diabetes. His blood glucose level in the ED was 387 mg per dL and his hemoglobin A1C was 8.4%. After discussing the pathophysiology of diabetes and the fact that Brett has most likely had impaired glycemia for 7 to 10 years, a comprehensive treatment program is discussed. Brett is advised to initiate the following treatment plans:
The patient should join the American Diabetes Association (ADA) to become better educated about this complex disease state. Membership online is available at http://www.diabetes.org/home.jsp.
He should begin a simple exercise program by walking 30 minutes 5 days a week. Additional testing will be necessary before Brett is prescribed a more vigorous exercise regimen.
Combination oral hypoglycemic therapy is initiated and the patient is given specific written instructions on taking the drugs in relation to mealtimes. The oral agents can be expected to lower his A1C 2% over 4 months to a target of 6.5% to 7%.
Because the patient is treatment na ve and new medication will be introduced, home blood glucose monitoring will be performed fasting and at bedtime on Monday, Wednesday, and Sunday each week. The blood glucose meter should accompany him to each office visit for downloading so that appropriate adjustments in his treatment regimen may be introduced if necessary.
Per the ADA treatment guidelines, low-dose aspirin will be prescribed to reduce the patient's risk of cardiovascular disease.1
He should reduce caloric intake by 150 calories per day. Although Brett is not severely obese, he is overweight, with a body mass index (BMI) of 31 kg per m2. The physician suggests stopping alcohol and regular sodas or limiting alcohol intake to less than 4 ounces per day, avoiding eating at fast food restaurants for lunch each day, and giving up his daily caramel macchiato (250 calories). Brett has also been skipping breakfast, yet he is so hungry during the day that he consumes at least two to three high-calorie snacks between 11 AM and 5 PM just to get by until dinner. By eating breakfast, Brett will not be as hungry during the day and the snacking will most likely stop.
Smoking is absolutely not acceptable for anyone, especially patients with diabetes. Brett, who smokes less than pack of cigarettes per day, is referred to the 1-800-QUITNOW telephone help line, which will provide him with the support needed to discontinue his use of nicotine.
Brett is also informed that he may require treatment for hypertension, elevated cholesterol, and proteinuria. These interventions will be discussed at his next outpatient appointment scheduled in 4 weeks.
Finally, Brett and his wife are reassured that having been diagnosed with diabetes will now afford him the opportunity to live and enjoy a much more healthy lifestyle. Although participation in diabetes self-management requires some extra work, lives can be saved and complications avoided if patients follow the suggestions made by their diabetes treatment team members. The importance of intensifying glycemic management immediately after being diagnosed and maintaining targeted glycemic control for 4 to 6 years has been shown to significantly reduce the risk of developing complications in patients with T1DM.2,3 Although we are uncertain whether this is also true for patients with T2DM, treating to the American Association of Clinical Endocrinologists American (AACE) and ADA A1C targets of 6.5% and 7% certainly seems prudent.
Successful long-term diabetes self-management requires the integration of pharmacotherapy, proper nutrition, home blood glucose monitoring, continuing patient education, an increase in physical activity, and surveillance for and prevention of short- and long-term complications. Although physicians are eager to prescribe pharmacotherapy to their patients, discussing issues such as home blood glucose monitoring, diet, and exercise are not second nature. Most physicians have had little direct training regarding lifestyle issue management with patients, preferring instead to refer to a dietitian or Certified Diabetes Educator (CDE). Primary care doctors must understand that they remain the director of the patient's management team. Although dietitians and CDEs can educate patients on lifestyle interventions, the physician is responsible for prescribing the actual dietary and activity parameters that patients follow.
Some PCPs have no access to ancillary personnel and may be their patients' only source of information regarding lifestyle modification. Either way, physicians who manage patients with diabetes should have a basic understanding of behavioral interventions as they relate to diabetes management. Spending 3 to 5 minutes per visit on lifestyle intervention could have a positive and motivational effect on patients. If, for example, a patient has been successful in losing weight, ask what techniques were used and never forget to praise his or her efforts. One should ask about exercise and smoking cessation at each visit. The physician should make certain that the patient knows the names of his or her medications and the times they should be taken. Determine what drugs need to be refilled so that lapses in treatment will be minimized. While sitting side by side with each patient, the physician should discuss the statistical evaluations of home blood glucose monitoring. Time spent on this will most certainly encourage the patient to continue monitoring. However, a patient who does take the time to monitor and brings the meter in for downloading will certainly become discouraged if no interest is shown in the glucose readings and the efforts are ignored.
Improving Adherence to Diabetes Self-Management Skills
Diabetes care can be improved by inviting the patient to become an active member of his or her own management team. Behavior changes are necessary to reduce long-term risks and maintain healthy lifestyles. By some estimates,
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less than 50% of patients with diabetes adhere to their recommended behavioral interventions.4 Adherence is multidimensional in that some patients may comply with medication regimens, while ignoring dietary or exercise recommendations. Others, who feel just fine, may exercise 2 to 3 hours a day so that they may avoid starting medications that are needed to manage hyperglycemia, hypertension, and hyperlipidemia. A study using a large national sample (National Health and Nutrition Examination Survey, NHANES) of patients with T2DM found that 29% of insulin-treated patients, 65% of those on oral medications, and 80% of individuals managed by diet and exercise alone either never performed self blood glucose monitoring (SBGM) or did so less than once per month.5
The findings from the recently published Cross-National Diabetes Attitudes, Wishes, and Needs (DAWN) Study6 showed patient-reported adherence rates for medication in T1DM and T2DM patients of 83% and 78%, respectively; self-monitoring blood glucose adherence was 70% and 64%, respectively; and appointment keeping adherence was 71% and 72%, respectively. The adherence rates observed for diet for T1DM and T2DM patients were 39% and 37%, respectively, and for exercise they were 37% and 35%, respectively. Providers reported significantly better adherence for T1DM than for T2DM patients across most treatment regimens.
Several factors have been shown to influence compliance with diabetes self-care, as summarized in Table 9-1. Demographic factors such as ethnic
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minority, low socioeconomic status, and low levels of education have been associated with lower regimen adherence and greater diabetes-related morbidity.8 For example, lower rates of self-monitoring blood glucose have been observed among minority African-American and Mexican-American patients.
TABLE 9-1 Factors That Favor and Promote Patient Adherence to Prescribed Treatment Regimens | |
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Patients with comorbid mental illness must have their psychological issues corrected before intensification of diabetes therapy is attempted (see Chapter 13). Both treatment compliance and outcomes are linked directly to the patient's affective state.15 PCPs should screen patients with diabetes for mental illness (schizophrenia, bipolar depression, major mood disorder, and generalized anxiety disorder) and initiate treatment when appropriate.
Family relationships play an important role in diabetes management. Greater levels of social support from spouses and other family members are associated with enhanced participation in diabetes self-management and reduce the stress associated with chronic disease management.8
One of the most important motivators of patient compliance is related to the amount of support received from the healthcare team members. Patients who are satisfied with their doctor-patient relationship are more adherent to their treatment program and participate more fully in diabetes self-management.11 One of the key elements to success in achieving good glycemic control for participants in the Diabetes Control and Complications Trial (DCCT) was the amount of support and availability patients received from their local healthcare study site.16
Factors that promote adherence include reminder cards and phone calls about upcoming appointments, minimizing delays in seeing patients once they arrive at the office, and reinforcing positive attributes of the visit, rather than focusing on the negative aspects of chronic complications.12,13
Patients prefer simplified treatment regimens to ones that are more complex and tend to accept the need to begin pharmacotherapy for diabetes much quicker than integrating lifestyle or behavioral changes into their daily lives.10,12
Is the Patient Noncompliant or Nonadherent ?
Physicians often relate interesting tales of patient noncompliance. Compliance is best defined as the extent to which a person's behavior coincides with medical advice. 13 Noncompliance implies that patients intentionally disregard or disobey the advice of their healthcare provider. Noncompliance provokes negative attitudes toward patients while discouraging patients from becoming active participants in their own diabetes self management. Adherence is viewed as an active, voluntary, and collaborative effort in a mutually acceptable course of behavior prescribed to produce a positive therapeutic outcome. 13 Patients who adhere to their treatment programs do so by choice, agree to participate in self-management, understand the implications of treating all metabolic abnormalities to target, and agree to become students of their own disease states. Once presented with a
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treatment plan and provided with the tools necessary to become successful at self-management, a patient may voluntarily choose to adhere to the prescribed plan, offer alternative suggestions to the professional team, or, most commonly, comply with the structured plan for a short time before becoming nonadherent. Patient adherence may be multidimensional. For example, patients may have no problems using four injections of insulin daily, yet only monitor their blood glucose levels once or twice daily despite warnings that failure to monitor may result in hypoglycemia.
In an attempt to enhance patient adherence to a prescribed treatment program, healthcare providers should consider the following options:
Allow patient adherence to evolve over time. Weight loss and increased physical activity can prevent or delay diabetes and complications related to prolonged exposure to hyperglycemia.17 Techniques that facilitate adherence to lifestyle changes can be adapted to primary care. Often the patient's readiness to work toward change must develop gradually. Patients facing the long-term task of adjusting their lifestyle benefit from assistance in setting highly specific behavior-outcome goals and short-term behavior targets. Individualization is achieved by tailoring goals and targets to the patient's preferences and progress, building the patient's confidence, and intensifying therapy as necessary to pursue these prescribed metabolic targets. Coaching patients can encourage positive choices, help them develop self-sufficiency, and assist the patient in identifying and overcoming their fears regarding lifestyle interventions. Patients who have multiple comorbidities (hyperlipidemia, hypertension, chronic renal failure, mental illness, severe clinical obesity, autonomic dysfunction) associated with their diabetes diagnosis should be referred to other specialists and ancillary personnel for intensive intervention education and management.
Target a single behavioral change rather than multiple interventions at each visit. When promoting behavioral or lifestyle changes, the physician should focus on a single intervention at each visit. For example, attempting to discuss appropriate timing of home blood glucose monitoring and smoking cessation at a single 15-minute visit is unlikely to yield any positive results. Diabetes is a stressful disorder, as is nicotine abuse. A discussion of diet, weight loss, exercise, and medication timing, while arranging for specialty evaluations to monitor for retinopathy, is too overwhelming for even the most dedicated patient.
Praise the patient at each visit. One should offer praise to each patient at the time of the follow-up appointment. As difficult as this may be for some physicians to accept, patients often do what they can in an attempt to find favor in the eyes of their healthcare team. Patients will bring in their glucose logs, their medication vials, or articles of interest that they read on diabetes management. Taking a minute to visually inspect these items means a great deal to patients. Those individuals who have been successful at weight
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reduction or smoking cessation or who initiated an exercise program should receive praise from the physician and a high five.Do not be afraid to change course. Some physicians may be reluctant to intensify diabetes treatment because they may view a deterioration in the patient's condition as a reflection of their own disease state mismanagement. However, diabetes is a chronic disease that is by nature progressive and a work in progress. Therefore, if one determines that a patient's glycemic control is not responding to the prescribed treatment, one should not hesitate to offer an alternative plan. The physician should remember to target success rather than accept failure. Patients do appreciate the efforts of their healthcare management team as long as they can be involved in the decision-making process.
Allow patients with poor glycemic control to be comfortable while intensifying their diabetes management. The patients with diabetes who are the most challenging to manage are those who have been under poor control for many years and have already experienced microvascular and macrovascular complications. These unfortunate individuals may have finally decided to get more active in their diabetes self-management, although reversal of end-stage disease is unlikely to occur. Treatment of these patients should still focus on lowering the A1C to the safest target. Patients who have spent the majority of their lives living with glucose levels in the 300 mg per dL range may not feel well when the glucose averages 150 mg per dL. They may develop adrenergic symptomatology suggestive of acute hypoglycemia as noted in Table 5-7. These uncomfortable symptoms tend to persist for 2 weeks before subsiding once the glycemic control is normalized. Patients who develop adrenergic symptoms should be reassured that they are simply adjusting their body sensors toward normal glycemic control. If they feel symptomatic, a blood glucose level should be obtained, and if it is 70 mg per dL or greater, no treatment should be attempted. Intensive diabetes management incorporates any modality that improves glucose control and lowers the AIC to target. Patients who feel miserable while treatment is intensified may become nonadherent to the prescribed protocol and linger in a state of persistent hyperglycemia.
Maintain a positive attitude for all patients, even those with end-stage disease. Physicians are unable to offer patients a cure for diabetes. However, the physician can provide patients with many therapeutic interventions to improve and maintain glycemic control, enhance quality of life, and treat many of the long-term diabetes-related complications. From a psychological and a physiologic viewpoint, physicians should attempt to allow patients to be as comfortable as possible with their chronic disease management. There are now excellent treatments for painful diabetic peripheral neuropathy that may improve patients' symptomatology within 2 weeks of beginning medication therapy. Men with erectile dysfunction can nearly always
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be treated successfully with oral medications, intraurethral pellets, or intracavernosal injections. Early interventions for patients with chronic kidney disease can slow the progression of this disease process. The use of statins and aspirin can improve outcomes in patients at risk for macrovascular disease. Physicians must always work for patients in an attempt to find therapies that can improve their quality of life and minimize future long-term complication risks. Often patients believe that having diabetes is a death sentence. In reality, with proper education and intervention, healthcare providers can always offer their patients hope for a brighter future of diabetes management. Physicians must never give up on any patient, no matter how challenging they may be.Identify and treat patients with comorbid depression. Identifying patients with significant psychosocial issues can improve treatment compliance. Fifteen percent to 20% of patients with diabetes have comorbid depression.15,18 These individuals may have a difficult time adhering to self-care behaviors and display worsening of their glycemic control. Treating patients who have major depressive disorder with antidepressants may improve adherence to diabetes self-management programs10 (see Chapter 13).
Individualize diet and physical activity treatment plans. Individual tailoring of diet and physical activity treatment plans is recommended by major guidelines focused on diabetes, obesity, and exercise.19,20 Placing patients on an 1,800 calorie ADA diet is inappropriate for patients who are lean, active, adolescent, elderly, acutely ill, or incapable of following pigeon-holed recommendations. Healthy food choices and flexible meal plans should be discussed. Patients should be made aware that diabetes is a disorder of carbohydrate metabolism. Simply avoiding sugar in the diet will not improve glycemic control. One should remind patients that glucose is the central nervous system's obligate source of energy. Without carbohydrate ingestion and glucose utilization, the body cannot survive. However, excessive ingestion of carbohydrates results in the inability of the pancreatic beta cell to produce enough insulin to prevent hyperglycemia. As hyperglycemia is prolonged, glucotoxicity destroys beta cells and other important tissues including the eyes, kidneys, nerves, and endothelial cells.
Patients often are overwhelmed by large goals that seem unachievable. Target behaviors should be phased, using small increments. The physical activity target can be gradually increased from setting a 4,000 steps per day goal for walking using an inexpensive pedometer, to more intense activity for longer periods, possibly with the assistance of a personal trainer. Group education sessions for patients with diabetes may be initiated with a 5- to 15-minute period of exercise. Patients should understand that any increase in physical activity is likely to improve hyperglycemia. By starting gradually, the patient can build confidence over time, with each stage having a higher likelihood of lasting success. Small advances also provide many opportunities for physician
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praise. Putting small steps together side by side will eventually encourage a patient to achieve the treatment target.Use visual imagery to demonstrate the relationship between hyperglycemia and glucose toxicity. A simple exercise in visual imagery might help patients understand the relationship between hyperglycemia and glucotoxicity. Patients who do not have diabetes have blood that is perfectly fluid in nature. Their blood is pure and fresh, similar to the water coming from a mountain stream. In contrast, hyperglycemia causes blood to become thick, sticky, and gooey, similar to maple syrup. As this hyperglycemic liquid flows through the body, the blood sticks to everything, including the eyes, kidneys, blood vessels, nerves, joints, muscles, tendons, skin, and beta cells. The longer the patient is exposed to hyperglycemia, the more likely he or she is to develop complications from kidney, nerve, eye, and heart disease. No one feels well with maple syrup running through the blood vessels. The clinician's job is to work with patients to allow them to have the syrup replaced by fresh mountain stream water.
Lifestyle interventions that may be used to improve patient adherence with diabetes self-management are summarized in Tables 9-2 and 9-3.
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Case 2
Despite concern over the continuing rise of his A1C from 7.2% 8 months ago to 8.6 % at this visit, Joseph has shown very little effort in participating in his diabetes self-management program. His physician has repeatedly advised him to avoid working the graveyard shift at the police department so that he can focus on improving his blood glucose levels. Joseph points out that as a junior member on the police force, he has little power to alter his schedule. In addition, Graveyard shift is not as busy as other shifts, so I'm not as stressed out. Last month, Joseph's physician dictated a letter to his police commander insisting that he be placed on the 6 AM to 2 PM shift for medical reasons. However, Joseph forgot to give the letter to his commander.
Joseph claims he is constantly checking his blood glucose levels, yet his meter downloads show inconsistency in monitoring (Fig. 9-1). Despite using four injections of insulin daily, he is checking, on average, only 1.2 blood glucose levels per day. On being confronted with this data, Joseph admitted that he could do better with home monitoring and will certainly make a better effort by the next appointment. The doctor asks Joseph how he can safely administer insulin without knowing his preprandial glucose level, especially because he is a police officer. Overdosing on insulin could have severe consequences for both Joseph and the public. Joseph, who has had T1DM for 2 years, replies that he simply guesses at what his blood glucose level might be before giving the insulin. Besides, I can pretty well judge how much insulin to give by the way I feel.
TABLE 9-2 Advanced Skills in Maintaining Lifestyle Changes | |||||||||||||||||||||||||||
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TABLE 9-3 Topics of Importance for the Successful Promotion of Diabetes Self-Management | ||||||||||||||||||||||||||||||||||||
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Figure 9-1 Download f Joseph's Glucose Monitor. Joseph's blood glucose meter download showing testing inconsistency despite Joseph's being on four injections of insulin daily. Prior to confronting the physician about his rising A1C levels and nonadherence to the treatment plan, this patient claimed that he was testing four times daily, once prior to each meal and at bedtime. |
Joseph's home blood glucose meter download data show that he is failing to check his glucose levels before lunch and dinner. He injects insulin four times daily often without knowing his preprandial glucose level. This can potentially lead to severe hypoglycemia. As a police officer, the patient is at risk of injuring himself or others if he develops hypoglycemia on the job. The patient is working a graveyard shift, so the mealtimes shown are adjusted to reflect Joseph's personal schedule. (Breakfast is eaten at 10 PM, lunch at 3 AM, and dinner at 9 AM.) Joseph is failing to check his blood glucose levels prior to bedtime (1 to 2 PM).
This is not the first time that Joseph and his physician have had this conversation. On three out of the last four visits, Joseph forgot to bring in his meter for downloading, despite being reminded to do so by phone 24 hours prior to his visit.
Joseph suggests that use of an insulin pump may help him get better motivated toward diabetes self-management. However, his doctor says that Joseph's continued failure to take an active role in his own care is cause for deep concern.
Perhaps taking insulin four times daily is not a reasonable option for Joseph at this time. Joseph agreed to pursue other treatment regimens, including beginning twice-daily premixed analogue insulin using a treat-to-target protocol. This would require twice-daily home blood glucose monitoring coupled with twice-weekly calls to the nurse for dose titration.
Joseph agreed to initiate this simplified yet nonphysiologic regimen. He was placed on 14 units of Aspart Mix 70/30 insulin using a pen injector before breakfast and dinner. Three days later he began his twice-weekly calls to the nurse to have his insulin doses titrated. The physician believed that Joseph's progress could be better monitored if he were to make the twice-weekly calls rather than entrust him with a forced titration insulin protocol schedule that he could self-manage. At his 3-month follow-up appointment, Joseph's point-of-service A1C had dropped to 6.9%. His meter downloads showed that he was becoming more consistent in home blood glucose monitoring and was even checking prior to exercise. Joseph still refused to change his shift, but both the doctor and the patient were pleased that his A1C has now reached a safer level.
Delegating Patient Care Responsibilities
In any therapeutic situation, especially those involving a chronic disease state, both the physician and the patient have specific responsibilities. The medical community now knows that, although a patient may be asymptomatic, hyperglycemia in the presence of comorbid metabolic disorders such as hypertension and hyperlipidemia will result in long-term diabetes complications. Achieving normalization of glycemic control requires active participation in self-management from the asymptomatic patient with diabetes. The medical team must enlighten, nurture, and continually guide the patient toward improved diabetes control. The responsibilities of both the patient and physician are noted in Table 9-4.
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TABLE 9-4 Defining Patient and Physician Responsibilities in Diabetes Management | ||||
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Discussing Medical Nutritional Therapy with Patients
The goals of medical nutrition therapy that apply to all persons with diabetes or prediabetes may be summarized as follows:
Attain and maintain optimal metabolic outcomes, including:
Achieve blood glucose levels in the normal range or as close to normal as is safely possible to prevent or reduce the risk for complications of diabetes
Minimize glycemic variability
Target a lipoprotein profile that reduces the risk for macrovascular disease
Lower blood pressure levels to reduce the risk for vascular disease
Prevent and treat the chronic complications of diabetes. Nutrient intake and lifestyle should be modified as appropriate for the prevention and treatment of obesity, dyslipidemia, cardiovascular disease, hypertension, and nephropathy.
Improve health through healthy food choices and physical activity.
Address individual nutritional needs, taking into consideration personal and cultural preferences and lifestyle while respecting the individual's wishes and willingness to change.
Goals of medical nutrition therapy that apply to specific situations include the following:
For youths with T1DM: Provide adequate energy to ensure normal growth and development, integrate insulin regimens into usual eating and physical activity habits.
For youths with T2DM: Facilitate changes in eating and physical activity habits that reduce insulin resistance, promote weight loss or minimize weight gain, and improve the overall metabolic status.
For pregnant and lactating women: Provide adequate energy and nutrients required to attain optimal outcomes.
For older adults: Provide for the nutritional and psychosocial needs of an aging individual.
For individuals treated with insulin or insulin secretagogues: Provide self-management education for the treatment (and prevention) of hypoglycemia, acute illnesses, and anticipated exercise-related blood glucose excursions.
For individuals at high risk for developing diabetes or those with prediabetes: Decrease risk or slow disease progression by encouraging physical activity and promoting food choices that facilitate moderate weight loss or, at least, prevent weight gain.
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The principles and strategies of nutrition and exercise for T1DM differ from those patients with T2DM. Patients must understand and determine the effect of diet and physical activity on their glycemic control to optimize diabetes self-management. Patients with T1DM dose insulin according to their anticipated carbohydrate intake and should be educated regarding the insulin-to-carbohydrate ratio (I/CHO). Healthy food choices, coupled with an active lifestyle, can be useful in minimizing weight gain, glycemic excursions, blood pressure elevations, and lipid levels in patients with T2DM.
Dietary Management for Type 1 Diabetes Mellitus
To maximize success as an insulin-dependent patient, each individual must be cognizant of the following relationships between insulin and food intake:
The onset of action and the duration of action of the prandial (bolus) insulin dose.
How much insulin is required to cover the expected glycemic excursions that will result from the consumption of a given amount of carbohydrates (I/CHO). This ratio may be stable throughout the day or may be variable, depending on the degree of the patient's insulin resistance.
The effect of fat content on carbohydrate absorption.
How insulin resistance varies during the day. Additional insulin will be required during periods of peak insulin resistance, whereas reduced doses will be needed during times of minimal insulin resistance.
What level of activity is planned as a dose of insulin is being absorbed. Moderate to heavy physical activity will require a 50% reduction in prandial insulin dosing.
Patients with autonomic neuropathy may have gastroparesis. If insulin is dosed as the patient begins to eat, the patient may develop immediate hypoglycemia due to the delay in nutrient absorption yet will experience postprandial hyperglycemia hours later as insulin levels wane while glucose levels peak.
Although these tasks seem daunting, with practice, most patients can learn the basic principles of medical nutritional therapy. With time, dietary management of diabetes not only becomes second nature but allows patients an opportunity to challenge their own nutritional skills to improve their glycemic control. The DCCT demonstrated that patients who adjusted their food intake and insulin dosage in response to preprandial blood glucose levels achieved lower A1Cs than did patients using conventional therapy.20a Rather than placing all patients on a specific diet (i.e., an 1,800-calorie ADA diet), mealtime flexibility should be encouraged, as patients dose insulin based on their carbohydrate intake. The physician should remember that patients are people too, and restricting food intake due to diabetes will lead to closet eaters and cheaters. One should allow patients to eat sensibly but insist that appropriate insulin be given for each meal. Checking a 2- to 3-hour postprandial
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glucose allows the patient to know if the dose given for a given meal was calculated correctly. If necessary, the patient can alter the dose of insulin the next time that same meal is eaten.
Food contains carbohydrates, fats, and proteins as sources of energy, as well as vitamins and minerals. The carbohydrates in food have the most impact on blood glucose levels. Foods that are high in fat content can contribute to obesity and heart disease while prolonging the time of carbohydrate absorption from the gut. Dietary fat, however, plays only a minor role in glycemic control. Protein is another minor player in short-term glycemic control: 50% of consumed protein is converted into carbohydrate over 4 to 6 hours. By constituting only 10% to 20% of the total daily calorie consumption, dietary protein does not have an impact on blood glucose levels.
Generally, all carbohydrates, the preferred energy source in the body, convert to glucose within 1 to 2 hours after consumption. Variables such as fat, fiber, and the glycemic load of a meal can alter the peak excursion of blood glucose. However, these are secondary to the total amount of carbohydrate consumed. Carbohydrate consumption must be balanced with insulin production and utilization. Insulin-requiring patients must use exogenous insulin to minimize the upward drive each gram of carbohydrate has on blood glucose levels. Patients with T2DM can balance carbohydrate consumption with exercise and medications, which either enhance the release of endogenous insulin by their pancreatic beta cells or improve insulin sensitivity within skeletal muscle cells and adipose tissue.
Insulin-to-Carbohydrate Ratios and Supplemental Insulin
I/CHO is used to determine how much exogenous (injected) insulin is required to cover a given quantity of carbohydrates. Patients with T2DM who are insulin-resistant and/or obese may have lower I/CHO and require more insulin; often 1 U of rapid-acting insulin analogue is needed to cover 5 g CHO. Conversely, lean patients with T1DM may have a much higher I/CHO and may only require 1 U rapid-acting insulin analogue for each 20 g CHO consumed.
Premeal and postmeal self-monitoring is the optimal way to determine the accuracy of the patient's carb counting and ability to respond with an appropriate insulin dose. There may be variations in the patient's I/CHO. Each patient will have a unique response to each meal and will need to learn to calculate his or her own individual I/CHO.
Patients should to be taught the many nuances of I/CHO.
Patients may have different meal bolus ratios for different times of day.
Meals with large quantities of fat result in delayed glucose availability.
If the premeal glucose level is within normal limits, the bolus insulin covers food intake only.
Low premeal blood glucose levels require less bolus insulin.
High premeal levels require enough insulin to bring glucose back to normal in addition to insulin to cover food.
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As with most insulin adjustments it is better to err on the side of caution. Excessive insulin doses should be discouraged. Some patients believe that avoiding hyperglycemia at all cost is critical to their well-being. Often these individuals will dose themselves into hypoglycemia, only to have to consume additional carbohydrates to reverse their lows. This will result in weight gain and increased insulin resistance.
To calculate a meal bolus dose of insulin based on carbohydrate consumption the rule of 450 is used:
450/total daily insulin dose = CHO covered by 1 U rapid-acting insulin analogue (lispro, aspart, glulisine)
An example of the 450 rule in use for an adult: A patient receiving a total of 50 U insulin per day:
450 50 U insulin = 9 g CHO per unit of rapid-acting insulin analogue
Patients may need to use supplemental insulin in addition to adjusting for carbohydrate intake if the preprandial blood glucose level is greater than 150 mg per dL. Supplemental insulin can be determined by the rule of 1,700, which predicts how much 1 U of insulin will lower the blood glucose level: insulin sensitivity factor (1,700 / total daily dose of insulin) (Table 9-5).
Patients should be instructed on the proper interpretation of food labels, which provide information regarding nutrients, calories, and serving sizes. A can of macaroni may contain 35 g of carbohydrates per serving, which in the example described in Table 9-5 would require 4 U of insulin coverage. Should the patient eat two servings of macaroni, a total of 8 U plus supplemental insulin for preprandial hyperglycemia would be required to cover this meal.
Some patients may benefit from purchasing carbohydrate-counting books that are available through the ADA (http://www.diabetes.org/home.jsp). Carbohydrate counting does take some practice and is more reproducible in patients having the best overall glycemic control.
We can do some carb counting for two apples one large, one medium and determine how much insulin is needed to consume each one. Apples are 13% carbohydrate by weight. A large apple weighs approximately 238 g, and a medium-sized apple weighs approximately 139 g. The carbohydrate content of each apple is as follows:
Large apple: 238 0.13 = 30.9 g of carbs
Small apple: 139 0.13 = 18.1 g of carbs
A patient with an I/CHO of 1:10 would need 3.1 U to cover a large apple but only 1.8 U for a medium one. If several foods are added to this meal, the carbohydrate content of each would be determined and added to the premeal carbohydrate count. If 80 g of carbs will be consumed, the patient will need to bolus 8 U of insulin.
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TABLE 9-5 How to Calculate the Insulin Sensitivity Factor (1,700 / total daily dose of insulin) | ||
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Dietary Management for Type 2 Diabetes Mellitus
Dietary intervention for patients with T2DM is designed to improve insulin resistance; reduce weight, when necessary; and promote adaptation of healthy food choices into the diet. Weight loss of 10 to 20 pounds can significantly improve insulin resistance and hyperlipidemia while controlling hypertension.21,22,23,24 Reducing calorie consumption, coupled with increased energy utilization with exercise, can result in improved weight management. By monitoring the effects of different foods on blood glucose levels, patients are able to understand the effects of food consumption on glycemic control.25
The Diabetes Food Pyramid
The Diabetes Food Pyramid divides food into six groups (Fig. 9-2). These groups or sections on the pyramid vary in size. The largest group grains,
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beans, and starchy vegetables is on the bottom. This means that patients should eat more servings of grains, beans, and starchy vegetables than of any of the other foods. The smallest group fats, sweets, and alcohol is at the top of the pyramid, suggesting that fewer servings of these items should be consumed.
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Figure 9-2 Food Guide Pyramid. (Adapted from National Center for Nutrition and Dietetics, the American Dietetic Association [www.aap.org], and the American Academy of Family Physicians [www.aafp.org].) |
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At the base of the pyramid are bread, cereal, rice, and pasta. These foods contain mostly carbohydrates. The foods in this group are made mostly of grains, such as wheat, rye, and oats. Starchy vegetables such as potatoes, peas, and corn also belong to this group, along with dry beans such as black-eyed peas and pinto beans. Starchy vegetables and beans are in this group because they have about as much carbohydrate in one serving as a slice of bread. Patients are advised to choose 6 to 11 servings from this group daily.
All vegetables are naturally low in fat and good choices to include often in meals or snacks. Vegetables are full of vitamins, minerals, and fiber. This group includes spinach, chicory, sorrel, Swiss chard, broccoli, cabbage, bok choy, brussels sprouts, cauliflower, kale, carrots, tomatoes, cucumbers, and lettuce. Starchy vegetables such as potatoes, corn, peas, and lima beans are counted in the starch and grain group for diabetes meal planning. Three to 5 servings of vegetables daily should be considered.
The next layer of the pyramid is fruits, which also contain carbohydrates. They also have plenty of vitamins, minerals, and fiber. This group includes blackberries, cantaloupe, strawberries, oranges, apples, bananas, peaches, pears, apricots, and grapes. Although 2 to 4 daily servings of fruit are suggested, their effect on blood glucose levels is greatest in the morning as insulin resistance is at its peak. Therefore, delaying fruit consumption until the afternoon when insulin resistance is reduced may help control glycemic excursions after meals.
Milk products contain a lot of protein and calcium as well as many other vitamins. The patient should choose nonfat or low-fat dairy products for the great taste and nutrition without the saturated fat. The ADA recommends 2 to 3 milk servings per day.
The meat group includes beef, chicken, turkey, fish, eggs, and tofu. Beans are in the starch group (1/2 cup of beans equals 15 g of carbohydrates, 3 g of protein, and no fat, unless cooked with bacon or ham). Other proteins in the meat group are peanut butter, cheese, and cottage cheese. Cheese is high in fat: Usually 1 ounce of cheese contains 8 g of fat. Meat and meat substitutes are great sources of protein and many vitamins and minerals. The patient should choose from lean meats, poultry, and fish and cut all the visible fat off meat. The portion sizes should be small. Three ounces is about the size of a deck of cards. Only 4 to 6 ounces per day divided between meals is recommended. The long-term effects of consuming more than 20% of energy as protein on the development of nephropathy has not been determined. However, intake of protein in the usual range does not appear to be associated with the development of diabetic nephropathy.19
The use of fats and sweets (such as potato chips, candy, cookies, cakes, crackers, and fried foods) should be minimized and consumed on special occasions such as birthdays or anniversaries.
The effect of alcohol on blood glucose levels depends not only on the amount of alcohol ingested but also on the amount of alcohol consumed in
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relationship to food intake. Alcohol is oxidized by the liver, where gluconeogenesis may become impaired, resulting in hypoglycemia. Because both insulin and alcohol can inhibit gluconeogenesis, patients with T1DM who inject insulin and drink alcohol without eating may develop severe hypoglycemia. Alcohol also increases triglyceride levels resulting in hyperlipidemia.25,26 In general, the effects of alcohol on glucose metabolism are not severe. Because insulin is not required to metabolize alcohol, no food group need be eliminated from the calculated intake. One must always remember that alcohol adds calories to the diet and, for this reason, is counted in the fat exchange group (Table 9-6). Patients with pancreatitis, dyslipidemia, or neuropathy should avoid the use of alcohol.25
TABLE 9-6 Calorie Content of Popular Alcoholic Beverages | |||||||||||||||||||||||||||||
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Case 3
Chelsea L. is 34 years old and has impaired glucose tolerance. She is 75 lb overweight and inactive. At her office visit, she asks your advice about beginning a low-carb diet that her neighbor recently used to drop 23 lb in 23 months. Chelsea wants to know if she might be successful with the same diet.
Points that can be discussed with Chelsea at the time of her visit include the following:
Low-carb diets are basically low-calorie diets. Carbohydrates like sodas, chips, snack foods, sweets, pastas, and rice are often the culprits of excessive intake. Of course, eliminating these excess calories will promote weight loss. As soon as the diet stops, the weight will be regained, often to the point above which the patient originally weighed.
Eliminating such an encompassing group of foods, including breads, cereals, fruit, and some vegetables, will result in the loss of important vitamins and fibers from a healthy daily diet plan. Patient may experience a change in bowel habits, dry skin, hair loss, irritability, sleep disturbances, headaches, and difficulty with concentration.
Low-carb diets teach nothing about portion control or moderation. They are an eat all you want approach that promotes no behavioral modification. When people reintroduce foods of which they have been deprived, poor eating habits will likely reappear, in conjunction with weight gain.
Instead of encouraging long-term reduction in carbohydrate consumption, one should encourage Chelsea to lose weight sensibly by modifying portion sizes, making wiser food choices based on the diabetes food pyramid, and adding exercise to her daily routine.
Case 4
Lisa is having difficulty adjusting to her recent diagnosis of T2DM. Since being placed on metformin 5 months ago, she has gained 22 pounds. Lisa claims that she does not overeat, and avoids sweets at all costs. Exercising is becoming increasingly more difficult as she continues to gain weight. Her BMI has increased from 33 to 37 kg per m2 in just 3 months. The nearest registered dietician is 75 miles away. Lisa is asking for advice on weight management because she realizes that excessive weight gain can worsen diabetes, hypertension, and her risk for cardiovascular disease. Fortunately, the patient who was scheduled to follow Lisa has canceled her appointment, meaning that you have some extra time to discuss dietary intervention.
Points to consider for Lisa include the following:
How can Lisa's nutritional status be effectively and efficiently determined at this time?
What expert advice can you provide to Lisa regarding weight management over the next 20 minutes?
Many individuals with T2DM diabetes are overweight, with 36% having a BMI of 30 kg per m2 or greater, which would classify them as obese.27 The prevalence of obesity is higher in women and members of minority populations with T2DM.27 As body adiposity increases, so does insulin resistance. Obesity may also aggravate hyperlipidemia and hypertension in T2DM patients.28
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Because of the negative effects of obesity on insulin resistance, weight loss is an important therapeutic objective for obese individuals with T2DM. Short-term studies lasting 6 months or less have demonstrated that weight loss in T2DM subjects is associated with decreased insulin resistance, improved measures of glycemia, reduced serum lipids, and reduced blood pressure.21 Long-term data assessing the extent to which these improvements can be maintained in people with T2DM are not available.
The reason that long-term weight loss is difficult for most people to accomplish is probably because energy intake and energy expenditure, and thereby body weight, are controlled and regulated by the central nervous system.29 Although our understanding of central nervous system regulation of energy balance is incomplete, it is thought that the hypothalamus may be the center of control. Neuropeptide Y, leptin, insulin, and a variety of other neural, endocrine, and gastrointestinal signals also appear to be involved. Individual characteristics of central nervous system control of energy balance may be genetically determined. Furthermore, environmental factors often make losing weight difficult for those genetically predisposed to obesity.
The National Weight Control Registry has enrolled more than 3,000 subjects successful at long-term maintenance of weight loss.30 A group of approximately 800 people who lost an average of 30 kg and maintained a minimum weight loss of 13.6 kg (30 lb) for 5 years were identified from the registry. Slightly more than half lost weight through formal programs, and the remainder lost weight with a program of their own. Average energy consumption was approximately 1,400 kcal per day, with 24% of energy derived from fat. Average energy expenditure through added physical activity was 2,800 kcal per week. Importantly, nearly 77% of this sample of people who were successful in achieving and maintaining weight loss reported a triggering event that preceded the weight loss. The most common triggering events were acute medical conditions and emotional problems. Thus, a new diagnosis of T2DM could trigger lifestyle changes that result in reduced fat and energy intake and increased physical activity and associated weight loss. Working diligently with Lisa (Case 4) so quickly after she was diagnosed with T2DM might increase the chance of successful weight reduction.
Exercise improves insulin sensitivity, can acutely lower blood glucose in patients with diabetes, and may also improve cardiovascular status. Exercise by itself has only a modest effect on weight. Exercise is to be encouraged but, like behavioral therapies, may be most useful as an adjunct to other weight-loss strategies, such as dietary fat reduction. Exercise is, however, important in long-term maintenance of weight loss.
Behavioral approaches to weight loss include strategies such as self-monitoring of food intake and exercise, nutrition education, stimulus control, preplanning food intake, and self-reinforcement. Weight loss with behavioral therapy alone has been modest31; behavioral approaches may be most useful as an adjunct to other weight-loss strategies.
For weight loss to be successful, focus should be placed on reducing dietary fat intake and spontaneous eating. By obtaining a nutritional history,
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one can estimate the number of excessive calories a patient consumes on a daily basis and offer suggestions on eliminating these wasted calories. Figure 9-3 provides a nutritional history form that can be completed by patients within 3 minutes. Once completed, physicians should evaluate the following information:
If the patient is eating only once or twice daily, there is a strong likelihood that snacks are being used to reduce hunger. Snacks can be high in calories and low in nutritional value. For example, a 4-oz serving of potato chips contains more than 500 calories and a 1.5-oz candy bar will cost the patient 225 extra calories. (Caloric content for food and beverages can be found online at http://www.annecollins.com/calories/.) Patients should be advised to eat three healthy meals daily. Snacking will be reduced if hunger is better controlled. Skipping meals will not result in weight reduction.
Eating meals outside the home can result in excessive caloric intake, especially when patients frequent fast food restaurants. (A normal caloric meal should be equivalent to the amount of food served while traveling by air with an economy class ticket.) A Quarter Pounder with cheese, large fries, and a large shake contains 1,200 calories. To burn off these calories, the patient will need to take a brisk 5-hour walk. Eating a regular hamburger and fries contains 475 calories, requiring the patient to walk only 2 hours to balance this caloric intake. A turkey sandwich brought from home for lunch contains only 350 calories, meaning that the patient has reduced the lunch caloric consumption by 125 calories.
One should watch out for food consumption that may add unnecessary calories to the daily diet. For example, Starbucks coffee houses serve up more calories than caffeine. A Caramel Frappuccino will cost the patient 280 extra calories (Table 9-7).
The physician should be wary of the patient who consumes fruity drinks. An 8-ounce cup of orange juice contains 100 calories. By using reduced calorie fruit beverages, calories can be reduced by 50%.
Figure 9-4 shows the relationship been TV viewing, physical activity, and the risk of developing diabetes. Inactive individuals who view more than 15 hours of TV per week have a three times higher risk of diabetes. Patients also tend to snack while watching TV, which results in situational food consumption and excessive daily caloric intake.
Do patients who are overweight really need to eat desserts on a daily basis? A cup of ice cream plus a slice of chocolate cake can cost 800 calories, almost one third of the daily caloric requirement of a 70-kg man. One should suggest that the patient consider eating desserts on special occasions, instead of as part of the daily routine. Patients who insist on eating dessert should consider eating fruit or nonfat yogurt as an alternative.
Simple changes in food and drink choices can reduce the daily caloric intake significantly. Skimmed milk has approximately 50% less calories than whole milk (150 cal per cup). Switching from regular to diet colas will eliminate 175 cal per 12 ounces consumed. Light beer has 100 cal per 12-ounce
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serving, whereas regular beer on average has 150 calories. One should be cautious about using sports drinks on a regular basis. Although these beverages are marketed to the general public, they basically add glucose, calories, and sodium to the diet. Elite athletes benefit more from sports drinks than persons with diabetes or prediabetes. An 8-ounce bottle of Gatorade contains 50 calories, whereas a 32-ounce bottle of POWERade will cost the consumer 280 extra calories. The clinician should encourage the use of light drinks for those who insist on using sports beverages.
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Figure 9-3 Nutritional Assessment Form. |
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Figure 9-4 Effects of Sedentary Lifestyle on the Development of Diabetes. This is the Health Professional's Follow-up Study (HPFS) that began in 1986 when 51,529 health professionals, ages 40 to 75 years, answered a detailed questionnaire about diet, lifestyle practices, and medical history. During 10 years of follow-up, 1,058 new cases of diabetes were diagnosed. After adjustment for age, average time spent watching TV was strongly associated with an increased risk for diabetes. This graph represents a multivariate analysis in which independent effects of watching TV and physical activity levels were observed. Reducing TV viewing and increasing physical activity can reduce the risk of developing diabetes. (Adapted from Hu FB, Leitzmann MF, Stampfer MJ, et al. Physical activity and television watching in relation to risk for type 2 diabetes mellitus in men. Arch Intern Med. 2001;161:1542 1548, with permission.) |
When using the Nutrition History Form (Fig. 9-3), one should determine the patient's basal metabolic requirements. The basal metabolic rate (BMR) is the minimum number of calories required to maintain the current body weight. The BMR is calculated as follows32:
BMR = 24 weight (kg)
The BMR is then multiplied by a number representing the individual's activity level:
Sedentary: BMR 1.45
Light: BMR 1.60
Medium: BMR 1.70
Heavy: BMR 1.88
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TABLE 9-7 Lisa's Nutrition Form | ||||||||||||||||||||||
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Lisa (Case 4) weighs 109 kg. Her BMR is 24 109 1.45 (because she has a sedentary lifestyle) = 3,793. The greater the caloric restriction below 3,793 per day, the more weight Lisa should lose. A pound is equivalent to 3,500 calories. Reducing the caloric consumption by 3,500 calories per week should result in 1-pound weight loss per week. By increasing the physical activity level, a person can possibly burn 1,750 calories per week while reducing caloric consumption by a similar amount, again resulting in a net loss of 1 pound per week.
Next, one should add up all the extra calories that Lisa is consuming on a near-daily basis. Lisa reports the following information on her nutrition form (Table 9-7).
Based on the fact that 3,500 cal = 1 pound, Lisa is gaining 1 pound every 10 days on her current diet. By simply eliminating these nonessential nutrients, eating three meals a day, and choosing foods from the diabetes food pyramid, Lisa can be expected to drop 1 pound every 10 days. If she also begins an exercise program, the weight reduction should occur more rapidly. One can also explain to Lisa that by simply reducing her caloric intake by 150 cal per day (equal to a cookie), she should lose 1 pound per month or 12 pounds per year.
The following are some additional ways that physicians may promote weight reduction for their patients. Writing these instructions on an actual prescription may increase the patient's awareness of the importance of adhering to these recommendations:
No second helpings at mealtimes.
Walk 30 minutes 5 days per week.
Avoid all sugar-containing drinks, desserts, and high-calorie snacks.
Drink at least 4 glasses of water each day.
TABLE 9-8 Dietary Recommendations for Patients with Diabetes and Coexisting Metabolic Disorders
Coexisting Metabolic Disorder Dietary Recommendations Hypertension - Weight reduction
- Reduce sodium intakea
- Low-fat diet that includes fruits, vegetables (5 9 servings/d), low-fat dairy products (2 4 servings/d)
- Food rich in potassium
- Reduce alcohol intake to <3 drinks/db
Dyslipidemia - For elevated LDL-C, saturated fats and trans-fatty acids should be limited to <7% of energy requirements
- For elevated triglycerides, low HDL-C and small dense LDL-C, improve glycemic control (consider insulin), modest weight reduction, dietary saturated fat restriction, and increase physical activity
Nephropathy - Restrict protein to 0.8 g/kg/d with the guidance of a registered dietician (overt nephropathy)
- Restrict protein to 0.8 1.0 g/kg/d for microalbuminuria
Acute illness - Ingest 45 50 g of carbs every 3 4 h should prevent starvation ketosis while keeping blood glucose levels at 80 180 mg/dL
LDL-C, low-density lipoprotein cholesterol; HDL-C, high-density lipoprotein cholesterol.
aFor gsalt-sensitive patients. No clinical measures are available that identify patients as being salt sensitive. Salt restriction can reduce systolic blood pressure by 5 mm Hg and 2 mm Hg for diastolic blood pressure. In general, the lower the sodium intake, the greater the effect on lowering blood pressure. The goal should be to reduce sodium intake to 2,400 mg or sodium chloride (salt) to 6,000 mg/day.
bAn association between high alcohol intake ( 3 drinks/day) and elevated blood pressure has been reported; however, there is no major difference in blood pressure between people who consume, <3 drinks/day and nondrinkers.
From American Diabetes Association. Nutrition principles and recommendations in diabetes. Position Statement Diabetes Care. 2004;27:S36.Stop all alcohol consumption.
Eat 3 meals a day. Do not skip breakfast.
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The nutritional recommendations for patients with diabetes and coexisting metabolic conditions are summarized in Table 9-8.
The Exercise Prescription for Diabetes
Exercise in the days before insulin we regarded as useful, but by no means did we appreciate it as vital in the care of diabetes. We should return to it to help us in the treatment of all of our cases.
Eliot P. Joslin, Treatment of Diabetes Mellitus, 1959
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Eliot Joslin, the first master clinician of diabetes, envisioned that not all of the mysteries of diabetes would be solved by the 1922 discovery of insulin. Historically, exercise has been a mainstay of diabetes treatment since the 1700s, when physicians advised their diabetic patients to ride long distances on horseback, believing that the friction of the body against the saddle would reduce the need to urinate and minimize dehydration. One could only imagine how many of these diabetic jockeys survived their trail rides. Although most patients today do not cite their fear of horseback riding as one of their many excuses to avoid exercising, motivating anyone to increase his or her physical activity presents a major challenge for PCPs.
The most common reasons why patients do not engage in regular exercise as part of their comprehensive diabetes self-management treatment plan include lack of time, health-related reasons (i.e., pain, fatigue, joint stiffness), boredom, lack of convenient exercise locations, and expense. Failure to exercise may also reflect a long history of obesity and inactivity, which is shared not only among people with diabetes but also in patients with schizophrenia.33,34 Patients who have developed diabetes-related complications, despite their previous attempts at behavioral interventions, may be reluctant to engage in any physical activity, especially as they become more symptomatic.
PCPs are well aware of the beneficial role exercise has on improving metabolic abnormalities related to hypertension, diabetes, hyperlipidemia, obesity, chronic pain disorders, and mental illness. Although anyone, even a nonphysician, can advise a patient about the benefits of exercise, physicians must assess their patients' general medical condition, determine any risks associated with exercising, and prescribe an individualized exercise regimen that is practical, safe, and likely to improve metabolic parameters. How can physicians best implement and integrate exercise into the overall treatment plan of diabetes?
Lisa (Case 4) is seeking the physician's advice on how she might better manage her battle against obesity. By adding exercise to her suggested caloric-restricted diet plan, Lisa can increase her calories expenditure and accelerate her rate of weight loss. Table 2-5 lists the amount of calories a patient can consume while participating in various types of physical activities. Endurance exercise might be difficult for Lisa because she has a low level of physical conditioning. One should consider having Lisa use a pedometer and have her begin walking at least 4,000 steps per day, the equivalent of 1 mile. One can add 1,000 steps per day, after 2 weeks until she can easily walk 10,000 steps daily. If she checks her pedometer after returning from work and notes that she has walked less than the number of targeted steps, Lisa could walk on the high school track near her home to make up for the deficiency. Over time, Lisa might decide to pursue a more strenuous form of cardiovascular or resistance exercise, perhaps under the direction of a personal trainer.
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Not all patients believe that reducing long- and short-term diabetes-related complications is the primary reason to initiate an exercise program. Some may view exercise as yet another burden imposed on them by their physicians or as punishment for being overweight. Other patients may consider exercise as being inherently unpleasant or stressful. To change a patient's perception regarding exercise, four principles should be followed:
Exercise is more likely to be attempted when the patient perceives the individual benefits of increasing activity on his or her own diabetes control. Exercise needs to be chosen by the patient rather than the physician and viewed by the patient as being valuable and reinforcing.
Exercise is likely to be sustained if the specific activity chosen has few barriers to implementation. Exercise must integrate easily within the patient's lifestyle, beliefs, and attitudes. Physicians can help patients clarify their choices.
The physician should not use exercise as a punishment. You must exercise or you'll have to find another doctor to take care of you! The rationale for exercise often presented to diabetic patients is the benefit to their glycemic control, which in turn is promoted as a means of avoiding complications (i.e., punishment). This rationale is a negative reinforcement paradigm in which patients are asked to do something to prevent a negative consequence. The motivating power is diminished in that the threatened punishment often will not occur for several years. Patients must also be educated to avoiding potential negative consequences associated with exercise (joint and muscle pain and feeling out of shape).
Exercise is more likely to be sustained if consistently reinforced by the healthcare management team and staff.
When initiating a discussion about exercise, one should consider how a patient may benefit from these positive attributes that are associated with increasing physical activity levels:
Health benefits, such as improvements in glucose regulation, weight control, lipid profiles, hypertension, and increased work capacity
Social benefits, such as increased interaction with family members, social others (i.e., training partners), and participation in organized, community-based activities
Psychological benefits, most notably reduced anxiety and depression, stress reduction, and enhanced feelings of well-being
In addition to the benefits of exercise, the following key points should also be discussed:
Exercise does not have to be done at Olympic levels while wearing spandex or designer clothing. More modest levels of activity can be quite effective.
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Ample research suggests that 30 minutes a day of moderate-intensity physical activity, such as brisk walking, performed 5 days a week will confer the majority of exercise-related benefits.17 Although 30 uninterrupted minutes is the ideal, three shorter, modest levels of activity will also be beneficial.Exercise should be viewed as part of a lifelong management program. The patient should not attempt to begin exercising at high intensity. A good program is one that progresses through a series of stages until an effective and acceptable level is achieved. Together, providers and patients should select a series of goals that are safe and effective over time in allowing patients to achieve their goals.
Patients will have to learn how to exercise properly (i.e., to perform the activity so that they avoid discomfort, injury, and problems with their diabetes). Proper stretching and warm-up activities are important. This will require them to be willing to experiment a bit with new behaviors, including adjusting their diabetes regimen. It also means that they will have to use effective equipment, especially properly fitting shoes and stockings.
Patients do not have to determine how to appropriately initiate an exercise program on their own. Healthcare professionals and others in their communities are there to help. The physician should consider establishing introductory group exercise classes at the office led by a certified personal trainer. A good trainer could make exercise an enjoyable, challenging, and rewarding experience for patients with limited exercise tolerance.
Patients should select activities that they are likely to continue in the long run. For example, if a patient is unable to swim, prescribing a water aerobics class may be unreasonable. Older patients may enjoy mall walking with other senior citizens. Martial arts studios offer a variety of cardiovascular classes for all age groups and also motivate and challenge participants to accelerate their levels of expertise.
Exercise should be a part of the patient's daily schedule. Although all patients have hectic lifestyles, taking time out for themselves is critical to maintaining a healthy mind and body.
Having laid this foundation, clinicians can now prescribe an exercise program that is likely to be a source of enjoyment and will be sustained over time. Exercise prescriptions should not be generalized. If advised to go out and start an exercise program today, a patient who is poorly conditioned is likely to finish a 5-minute jog feeling worse than yesterday when the day was spent watching football on TV. Exercise will immediately be viewed negatively, similar to having to pay taxes on April 15.
One should start exercise prescribing by discussing the following questions with the patient:
What are your goals for exercise? Do you want to lose weight, improve your blood pressure, improve your A1C, improve your physical conditioning, prevent heart disease, improve your chance of fertility, or become a world-class
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swimmer? A patient's goals may parallel or be totally at odds with those of the clinician. Whatever the goals, one should not be judgmental. The clinician should remember, the rationale might not reflect what the clinician feels is most important, but it may result in achieving the same end point.What types of physical activity do you like to do or think you would like to try? This question is designed to help guide patients in selecting an appropriate activity that they are motivated to do. If they do not have a strong sense for what they want, a useful strategy is to ask them to indicate their preference between the following options: (a) long- or short-duration exercise, (b) high- or low-intensity exercise, (c) exercising alone or with others, (d) exercising at home or at a facility, (e) exercising indoors or outdoors, and (f) participating in a competitive or cooperative sport.
If a patient is unable to list any types of physical activities that may be suitable, suggestions should be offered based on the completed patient-directed daily activity profile (Table 9-9). The clinician should seriously consider establishing group exercise programs that may introduce patients to safe and inexpensive forms of physical activity. Highly motivated physicians may even consider participating or leading these classes themselves. Once patients have narrowed down the possibilities or even selected specific exercise activities, the physician should help them address the second axiom: Physical activity must be realistic and feasible in order for it to be sustained.
Questions that should next be considered include the following:
Does the chosen activity require special facilities? A variety of activities (swimming, martial arts, tennis) can only be performed at dedicated facilities. Perhaps joining a local health club, fitness center, or YMCA will allow the patient to have access to multiple activities under one roof. Are the facilities easily accessible and in proximity to the patient's home?
Does the physical activity require special equipment? Is the necessary equipment available and affordable?
Does the physical activity require special training? Are training opportunities readily available, scheduled at convenient times, easy to get to, and affordable? Physicians may wish to solicit discounted memberships from local gyms, YMCAs, martial arts studios, and health clubs for use by patients.
Does the physical activity require group involvement? Several sports require one or more additional people to play. Will patients always be able to find partners when they want or need to play?
Is the physical activity seasonal? To maintain a regular exercise program, patients choosing these will need to have alternate activities that they enjoy in the off-season. For example, cross-country skiing can be replaced by mountain biking.
The physical limitations related to diabetes comorbidities should be addressed individually (Table 9-10).
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TABLE 9-9 Patient-Directed Daily Activity Profile | ||
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After beginning an exercise program, helping patients stay motivated to continue their physical activity is critical to successful diabetes lifestyle management. Motivational tips that might help patients stay on track with their exercise program include the following35:
One should advise patients to avoid the temptation to do too much too fast. Patients should gradually build up their level of physical conditioning to avoid injury, fatigue, pain, and discouragement and always use proper equipment while exercising.
The patient should monitor blood glucose levels before, during, and after exercise to understand the effects of physical activity on individual glycemic control. Some patients may experience hypoglycemia 12 to 16 hours after completing their training session. The patient should be aware of the symptoms of hypoglycemia (weakness, lethargy, confusion, loss of muscle strength, increase sweating, blurred vision all of which may also be symptoms of excessive exercise intensity). If symptomatic, the patient should check the blood glucose levels and treat the hypoglycemia appropriately.
The patient should know the pre-exercise targets for safe glycemic control while exercising. If the blood glucose level is outside of the safe range, what interventions should be used to prepare for exercise? The patient should learn to adjust medications (especially insulin) prior to exercise. (One useful method to recommend is keeping a training log that includes monitoring results to help patients remember what did and did not work for them.)
The patient should schedule exercise in advance. Setting a schedule will help patients avoid conflicting activities. A regular exercise schedule for patients with T1DM will also help them more effectively adjust their regimen so that they better control their diabetes.
TABLE 9-10 Exercising with Diabetes Complications: Risks and Recommendations
Comorbidity Retinopathy Nephropathya Autonomic/Peripheral Sensory Neuropathy Risks Increase blood pressure
Increase retinal hemorrhagesHemodynamic changes
Exacerbated hypertension
Coexisting retinopathy is likelyImpairment of temperature control
Orthostatic hypotension
Diarrhea
Dehydration
Foot ulcerations
Callus formation on feet
Difficulty maintaining balance
Higher risk of sudden death due to acute MIRecommendations for exercise Walking
Swimming
Low-impact aerobics
Stationary cycling
Endurance exercisesLow impact, non-weight bearing activities (swimming) Swimming
Bicycling
Rowing
Chair exercisesContraindicated exercises Power lifting
Valsalva
Boxing
Martial arts
Jogging
Racquet sports
Strenuous trumpet playing
High-impact aerobicsWeight training
Valsalva maneuvers
Calisthenics in patients with left ventricular dysfunctionTreadmill
Prolonged walking or jogging
Step aerobicsMedical evaluations DR every 12 months
Mild NPDR every 6 12 months
Severe NPDR every 2 4 months
PDR every 1 2 monthsAmbulatory blood pressure monitoring during exercise might be considered Comprehensive cardiovascular exam should be performed prior on all patients with autonomic dysfunction prior to initiating exercise
Always promote adequate hydration and blood glucose monitoring before, during and after exercise
Avoid exercising in extreme heat or cold environmentsMI, myocardial infarction; DR, diabetic retinopathy; NPDR, nonproliferative diabetic retinopathy; PDR, proliferative retinopathy.
aSpecific physical activity recommendations have not been developed for patients with incipient (microalbuminuria >20 mg/min albumin excretion) or overt nephropathy (>200 mg/min). Patients with overt nephropathy often have a reduced capacity for physical activity, which leads to self-limitation in activity level. Although there is no clear reason to limit low- to moderate-intensity forms of activity, high-intensity or strenuous physical activity should probably be discouraged in these individuals unless blood pressure is carefully monitored during exercise.
From American Diabetes Association. Physical activity/exercise and diabetes. Position Statement. Diabetes Care. 2004;27:S58 62. and Marrero DG. Time to get moving: helping patients with diabetes adopt exercise as part of a healthy lifestyle. Clin Diabetes. 2005;23:154 159.Getting a training partner may be motivational. If the training partner is not a family member, the physician should counsel the patients to discuss their diabetes with their partner, managing suspected hypoglycemia and dehydration.
The patient should set realistic exercise goals. Exercise goals need to be precisely defined and realistically attainable. It is also important that the goals be defined by exercise behavior (e.g., walk for 30 minutes 3 times per week ) rather than defined by an outcome of exercise behavior (e.g., lose 20 pounds ).
To reduce boredom, the physician should help patients identify alternative exercise activities. The patient should learn to cross train using different activities. After performing the same physical activity for several months, the skeletal muscles involved with that exercise become extremely efficient at performing those movements. Although sports-specific exercises may be an excellent way to prepare for participating in certain types of sporting events, such as skiing, the level of physical conditioning will not be increased if the same exercise is performed during each session. Rather than continuing to improve, patients may become bored as they simply maintain a certain level of fitness. Cross training also reduces the risk of developing painful overuse syndromes as different exercises work different muscle and tendon groups. Participants in cross-training conditioning can choose from a long list of activities that they may choose to perform several times a week:
Cardiovascular Exercise
Running, treadmill
Swimming
Cycling (recumbent, stationary, mountain biking)
Rowing
Stair climbing, elliptical machines
Racquetball, basketball, tennis
Resistance Training
Calisthenics (push ups, crunches, pull ups)
Free weights
Weight machines, cable machines
Circuit training
Flexibility
Stretching (should be done prior to each exercise session to prevent injury)
Yoga
Pilates
Tai Chi (excellent for patients with muscle and joint pain)
The physician should explain the difference between failure and backsliding. Any deviation from a schedule or failure to meet expectations is viewed as failure. Even world-class athletes will experience burnout and need to take time off from conditioning. This should be considered as a temporary backslide rather than a permanent failure. Most patients will get back on track quickly, possibly after taking on a different form of physical activity. Patients should be told to tackle the future and not haggle over the past.
The physician should reinforce the patient's efforts for lifestyle intervention at each office visit. One can comment on parameters such as weight loss, body fat reduction, reduction of the BMI or waist circumference, improvement in A1C or lipid values, and emotional affect since the previous visit. Simply telling the patient that he or she looks great when compared with the previous office visit will go a long way to maintain the patient's motivation toward a positive change. One should make certain to inquire about the patient's current exercise program and suggest ways in which the activity level may be safely intensified or adjusted. If the patient is experiencing burnout, suggest alternative exercises such as yoga, Pilates, or martial arts. Jogging on a treadmill can become boring for some patients after just a few weeks. A change in scenery would be welcomed by most patients who are losing interest in their prescribed physical activity.
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Clinicians should always remember that despite their best efforts and motivational discussions, not all patients will have any intention or desire to become more active. Directing one's personal frustration toward these patients would only be counterproductive. Those patients who do increase their activity level will undoubtedly appreciate the time and efforts put forth by their primary care doctor. Physicians who can successfully motivate patients into becoming more active will enjoy coaching them toward having a better mind and body.
Pre-exercise Evaluation
A detailed medical evaluation with appropriate diagnostic studies is indicated for patients having any macrovascular or microvascular complications, which may be worsened by exercise. Identification of at-risk patients will allow the physician to design an individualized exercise prescription capable of minimizing risks. The pre-exercise history and physical examination should focus on symptoms and signs of diseases affecting the heart, vascular system, eyes, kidneys, feet, and nervous system.
Patients who require a graded exercise test prior to prescribing an exercise program include the following36:
Patients with diabetes who are planning to initiate moderate- to high-intensity physical conditioning
Patients at risk for underlying cardiovascular disease:
Age greater than 35 years
Age greater than 25 years and
T2DM greater than 10 years' duration
T1DM greater than 15 years' duration
Presence of any additional risk factors for coronary artery disease (CAD) (smoking, hypertension, hyperlipidemia, proteinuria, family history of CAD, hyperuricemia, obesity, and laboratory evidence of elevated highly
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sensitive C-reactive protein, B-type natriuretic peptide, homocysteine, renin, or urinary albumin-to-creatinine ratio).37Presence of microvascular disease (proliferative retinopathy, nephropathy, microalbuminuria, peripheral sensory neuropathy)
Peripheral vascular disease
Autonomic neuropathy
Patients who exhibit nonspecific electrocardiogram (ECG) changes in response to exercise, or who have nonspecific ST and T wave changes on resting ECG, should undergo alternative testing such as dobutamine-atropine stress myocardial perfusion imaging radionuclide stress testing,38 stress echocardiogram,39 or single-photon emission computed tomography (SPECT) scan.40
Patients planning to participate in low-intensity forms of physical activity, such as walking, should have additional pre-exercise studies performed based on sound clinical judgment (Tables 9-11 and 9-12). Patients with known CAD or left ventricular dysfunction should be referred to a cardiologist for pre-exercise testing.
Preparing to Exercise
A proper exercise session should include a warm-up, endurance phase, and cool-down period. The warm-up should consist of 5 to 10 minutes of aerobic activity (walking, cycling, and/or stretching) at a low-intensity level. Following the warm-up, muscles should be gently stretched for another 5 to 10 minutes. Focus should be placed on stretching those muscles that will be worked maximally during the endurance phase. The endurance phase of
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exercise requires the patient to attain and maintain the desired heart rate (Table 9-11) continuously for 15 to 20 minutes. Thus, a 50-year-old patient who desires to pursue hard physical activity will need to maintain a heart rate of 220 - 50 = 170 0.85 = 144 beats per minute for 15 to 20 minutes. The cool-down and warm-up phases are similar in their intensity and duration. The cool-down phase is designed to gradually bring the heart rate down to the pre-exercise level.
TABLE 9-11 Classification of Physical Activity Intensity Based on Exercise Lasting Up to 60 Minutes | ||||||||||||||||||||||||
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TABLE 9-12 Borg 6 20 Relative Perceived Exertion Scalea | ||||||||||||||||||
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The basic principles of safely exercising with diabetes include the following:
The clinician should encourage aerobic conditioning.
The patient should make certain that foot care is proper (wear socks, keep feet dry, use orthotics when necessary).
The patient should wear a diabetes identification bracelet or shoe tag.
Proper hydration is necessary before, during, and after exercising. At least 17 ounces of fluid should be consumed 2 hours before exercising. During physical activity, fluids should be taken early and often in an amount sufficient to compensate for loses in sweat reflected in body weight loss or the maximum amount of fluid tolerated.
The patient should avoid exercising in extremely hot or cold environments.
Free weight training may be acceptable for young individuals with diabetes but not for older patients or those with long-standing diabetes. Patients
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with microvascular and macrovascular complications should avoid resistance training.Moderate weight training programs using light weights, cables, and Nautilus-like machines using light weight with frequent repetitions can be used for maintaining or enhancing upper body strength in nearly all patients with diabetes.
Exercise and Type 1 Diabetes
The primary concern of patients with T1DM who participate in exercise is to avoid hypoglycemia. This requires that the patient understand the metabolic and hormonal responses to physical activity and is well trained in diabetes self-management skills (home blood glucose monitoring, carb counting, hydration, management of hypoglycemia, detection of urinary or serum ketones, and sick day protocols). The increasing use of intensive insulin therapy has provided patients with the flexibility to make appropriate insulin dose adjustments for various activities. The rigid recommendation to use carbohydrate supplementation calculated from the planned intensity and duration of physical activity, without regard to glycemic level at the start of physical activity, the previously measured metabolic response to physical activity, and the patient's insulin therapy is no longer appropriate. Such an approach not infrequently neutralizes the beneficial glycemic-lowering effects of physical activity in patients with T1DM.
General guidelines that may prove helpful in regulating the glycemic response to exercise include the following:
Metabolic control before exercise:
The patient should avoid exercise if fasting glucose levels are higher than 250 mg per dL and ketosis is present and use caution if glucose levels are higher than 300 mg per dL and no ketosis is present.
The patient should ingest an additional 15 g of carbohydrate if glucose levels are less than 100 mg per dL.
Blood glucose monitoring before, immediately following the conclusion of the exercise session, and 4 to 12 hours after ending heavy physical conditioning. The patient should identify when changes in insulin or food intake are necessary.
The patient should learn the glycemic response to different exercise conditions.
Food intake:
The patient should consume added carbohydrate as needed to avoid hypoglycemia.
Carbohydrate-based foods should be readily available during and after exercise.
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As opposed to patients with T2DM, studies have failed to show any long-term improvement in A1C levels associated with exercise performance in patients with T1DM. However, because physical activity can improve cardiovascular fitness, lower blood pressure, and improve lipid profiles, exercise should be strongly encouraged in patients with T1DM. The process of physical conditioning through exercise training can result in a 20% to 30% reduction in daily insulin requirements.41
Exercising with an Insulin Pump
Using an insulin pump is advantageous for people who desire to participate in regular physical activity, especially when the exercise is at a moderate or intense level for more than 30 minutes. If exercise times are consistent, the pump basal rate can be reduced by 50% 60 to 90 minutes before the anticipated start physical exertion. Patients with well-controlled T1DM who use insulin pumps can perform 30 minutes of mild to moderate exercise beginning 2 to 3 hours after breakfast without risking hypoglycemia.42
The increased metabolic demands that accompany exercise require an increase in fuel mobilization from sites of storage (liver and adipose tissue) and an increase in fuel utilization by the skeletal muscles. These physiologic accompaniments to exercise are controlled by precise endocrine responses to physical activity. Unfortunately, these methods of endocrine control are lost in patients with T1DM and the glycemic response to exercise depends on the following factors:
Exercise intensity, duration, and type (aerobic or anaerobic training)
Fitness level and nutritional status of the patient
Temporal relationship between physical activity and mealtime
Temporal relationship to previous insulin bolus and basal insulin level
Site of insulin administration
Overall level of glycemic control
Presence of diabetes-related complications
During the transition from rest to exercise, the skeletal muscles shift from using free fatty acids to glucose and glycogen for the primary energy source.43 As exercise duration exceeds 60 to 90 minutes, glycogen levels are depleted, leaving free fatty acids and glucose to supply skeletal muscles with energy. Glucose becomes the primary source of energy during exercise as hepatocytes shift from glycogenolysis to gluconeogenesis. Circulating insulin levels play a major role in maintaining glucose homeostasis during prolonged exercise (Fig. 9-5). When free insulin levels are elevated, glycogenolysis and gluconeogenesis will both be impeded. Free fatty acid levels will also be reduced, and exercising skeletal muscles will have no source of energy. The athlete will develop hypoglycemia and weakness in response to exercise. Higher levels of insulin will also block glucagon release from the pancreatic alpha cells further reducing the body's ability to respond to hypoglycemia.
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Figure 9-5 Blood Glucose Homeostasis in Response to Exercise. Sources of energy during exercise include free fatty acids (FFAs) originating from adipose tissue and glucose derived from hepatic gluconeogenesis and glycogenolysis. Glucose uptake by skeletal muscle cells is insulin independent yet enhanced by circulating insulin levels. Some insulin is needed during exercise to overcome elevated levels of FFAs and counterregulatory hormones (glycogen and glucagons), which can induce hyperglycemia and ketosis. |
If the circulating insulin levels are low, free fatty acid production, glycogenolysis, and gluconeogenesis will all be accelerated. Glucagon levels will also rise resulting in hyperglycemia and possible diabetic ketoacidosis (DKA).
The principles to safely exercising with an insulin pump include the following:
The patient should understand the association between metabolism and physical activity. Some activities, such as resistance or high-intensity interval training, stress mainly anaerobic energy sources and can have a markedly different effect on glycemia compared with prolonged or mild aerobic exercise.
The patient should establish glycemic patterns. Patients should be knowledgeable about their usual glycemic response to exercise. For example, mild exercise may require no adjustment in pre-exercise basal rates, whereas moderate to heavy exercise will necessitate a 50% basal rate reduction. Patients will need to adjust their pump parameters based on their individual response to exercise.
The patient should understand carbohydrate requirements for exercise. Carbohydrate consumption should be made according to the predicted glycemic response to physical activity. The patient should monitor glucose
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levels frequently during sustained exercise lasting more than 30 minutes and provide additional carbohydrates to maintain blood glucose levels in the range of 120 to 180 mg per dL.The patient should expect a training response to glycemic control over time. Active patients should notice a glycemic training response occurring after exercising consistently for 2 to 3 weeks. Training increases fat utilization and potentially spares blood glucose. This response may reduce the need for regimen changes during prolonged aerobic activities. In addition, as muscle mass increases in response to training, an individual's overall insulin sensitivity may increase, which may allow for lower basal and bolus insulin doses.
If the blood glucose level is lower than 100 mg per dL, the patient should suspend or reduce the basal insulin rate during exercise. However, physical activity lasting more than 30 minutes may require consumption of additional carbohydrates to prevent exercise-induced hypoglycemia.
Patients may exercise if the blood glucose level is less than 250 mg per dL and no ketones are present in the urine. If blood glucose levels are greater than 250 mg per dL and no ketones are present, a small bolus of insulin may allow the patient to safely exercise. If ketones are found and the pre-exercise level is greater than 250 mg per dL, exercise is ill advised.
Exercise and Type 2 Diabetes
Habitual aerobic fitness and/or physical activity are associated with significantly lower cardiovascular and overall mortality to a much greater extent than could be explained by glucose lowering alone. Wei et al.44 reported on 1,263 men with T2DM who underwent a detailed examination, including a maximal treadmill exercise test with ECG monitoring, physical exam, and blood tests between 1970 and 1993. Mortality over the course of their study participation was the primary endpoint. After nearly 12 years of follow-up, mortality in the moderate-fit group was ~60% lower than in low-fit men. Low-fit men had a 2.2-fold greater mortality risk compared with men having moderate or high fitness levels. Mortality rates in men with T2DM who did not participate in any physical activity were 1.8-fold higher than in men who were active participants in exercise. Interestingly, low-fit men also tended to have multiple cardiac risk factors including nicotine abuse, hyperlipidemia, hypertension, and obesity.45
The recommended exercise prescriptions for patients with T2DM from the American College of Sports Medicine (ACSM) and the American Diabetes Association are listed in Table 9-13.
Because of the increased evidence for health benefits from resistance training, the ACSM now recommends that resistance training be included in fitness programs for adults with T2DM.46 With advancing age, there is a tendency for progressive declines in muscle mass, increased adiposity, and
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increased insulin resistance, all of which can be improved with resistance training.47 Resistance exercise improves insulin sensitivity to about the same extent as aerobic conditioning.48
TABLE 9-13 Recommendations of Major Professional Associations on Types and Amounts of Physical Activity | |||||||||||||||||||||||||||||||||||||||||||||||||
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Patients with T2DM who exercise can improve the following metabolic parameters:
Carbohydrate metabolism and insulin sensitivity. Moderate exercise three to four times a week lasting 30 to 60 minutes improves A1C levels 10% to 20% from baseline. Patients with the most severe insulin resistance show the greatest improvement in A1C levels.36
Prevention of cardiovascular disease. Patients with T2DM and metabolic syndrome are at risk for premature CAD, hypertension, hypercoagulation, hyperinsulinemia, central adiposity, and atherogenic dyslipidemia. Poor aerobic fitness levels are associated with many of the same cardiovascular risk factors. Exercise will lower plasma insulin levels and improve insulin sensitivity at the site of the skeletal muscle and adipose tissue, thus benefiting the cardiovascular status of physically active individuals.49,50
Hyperlipidemia. Regular physical activity reduces triglycerides and may improve high-density lipoprotein cholesterol (HDL-C) levels in patients with diabetes.49
Hypertension. Reducing circulating insulin levels in patients can reduce blood pressure.49
Obesity. Although data suggest that physical activity may enhance weight loss, weight reduction and weight maintenance are best accomplished when calorie-restricted diets are used in conjunction with regular physical activity. Exercise appears to reduce levels of intra-abdominal fat, which can increase levels of adiponectin, and reduce insulin resistance.49
Prevention of T2DM. Weight reduction combined with regular moderate exercise has been found to delay or prevent diabetes in three published trials.17,51,52
Traveling Tips for Patients with Diabetes
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Case 5
As the holiday season approaches, your nurse advises you that Mrs. Harlig is planning to fly from Los Angeles (LA) to New York next week. Prior to departure, she wants to know if any adjustments need to be made to her insulin pump parameters while traveling. She asks the following questions:
How should she dose insulin if her pump malfunctions?
What, if any, diabetes supplies should be brought on board the plane?
Also, could you please write her a note so she could get on board the plane with her insulin pump?
Her 25-year-old sister, who also has T1DM, will be accompanying her back to LA from New York. The sister is on a basal-bolus regimen using insulin glargine and lispro. Should she make any adjustments in her insulin regimen in preparation for the nonstop flight home?
Some of the most confusing issues facing patients with diabetes are those related to travel. No guidelines are published that advise patients on adjusting their medication schedule as they travel across time zones. Physicians may get frequent requests to write notes allowing patients to travel on a plane with their diabetes supplies. Should the time on the insulin pump be changed while traveling? What additional supplies and medications should patients bring with them to their travel destination and should they be carried on board the plane or packed away in the checked baggage? When should patients on oral agents take their prescribed drugs while traveling across time zones?
The first priority in managing traveling diabetes patients is to determine if they are safe to travel in the first place. For example, a patient who was just released from the hospital after being treated for DKA due to an acute viral illness may require 2 weeks of observation prior to boarding a plane. A relapse of the patient's illness could result in a recurrence of DKA. Patients who recently experienced a deep venous thrombosis, a transient ischemic attack, a cardiac arrhythmia, or any other acute illness should be advised to see their PCP at least 4 to 6 weeks in advance of travel to make certain that they qualify as safe travelers.
Patients requiring special diets should be advised to follow this procedure:
Request the special diabetic meal with your reservation.
Reconfirm the meal has been ordered at least 48 hours before departure.
Ask at check-in if the meal request is in the computer.
Ask the galley attendant after boarding, yet prior to takeoff if the meal was loaded on board.
Hand the flight attendant a note with your name, seat assignment, and meal preference prior to departure.
Patients should be informed that diabetic meals are geared more toward patients with T2DM. If patients are anxious about what they are given to eat on airlines, they should pack their own meals and snacks in their carry-on baggage. Skipping a meal may actually help reduce the effects of jet lag.53
No matter where one travels, passing through security checkpoints can develop into an uncomfortable adventure. The ADA has partnered with the Transportation Security Administration (TSA) to develop travel tips for individuals with diabetes. Patients should notify security screeners that they have diabetes and are in possession of diabetes-related supplies. The following
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diabetes-related supplies and equipment are allowed through the checkpoint once they have been screened:
Insulin and insulin-loaded dispensing products (vials or box of individual vials, jet injectors, pens, infusers, and preloaded syringes) that are clearly identified and labeled
Unlimited number of unused syringes when accompanied by insulin or other injectable medication
Lancets, blood glucose meters, blood glucose meter test strips, alcohol swabs, meter-testing solutions
Insulin pump and insulin pump supplies
Glucagon emergency kit clearly identified and labeled
Urine ketone test strips
Unlimited number of used syringes when transported in sharps disposal container or other similar hard-surface container
A visual inspection of diabetic supplies may also be requested. However, this request must be made prior to beginning the x-ray inspection process. Prior to requesting a visual inspection, patients should do the following:
Patients should place medication and associated supplies into a separate plastic baggie for inspection at the security checkpoint.
Patients should have all medications labeled and identifiable.
Patients will be responsible for displaying, handling, and repacking their own medication and supplies during the visual inspection process.
Any medications or supplies that cannot be cleared visually must be submitted for x-ray screening. Refusing x-ray screening will preclude the supplies or medications from being carried on board the airplane.
Notes from physicians attesting to the patient's diagnosis of diabetes are not accepted by security screeners because they are easily forged.
Insulin pumps and sensors can safely pass through metal detectors or be handwanded. Some screeners will test the pump and sensor for explosive residue after passing through the metal detector. Most pumps will not set off the metal detector alarms at the security checkpoints. However, if pumps are contained within a zippered pouch, the metal in the pouch will set off an alarm. When subjected to a pat-down, the patient should advise the screener that neither the pump nor the sensor can be removed because they are connected via catheters or wires that are inserted under the skin. Fortunately, TSA screeners are quite comfortable recognizing patients with insulin pumps, although few have seen the sensor-augmented pumps. Some screeners actually wear pumps themselves.
As a courtesy, screening personnel should be forewarned when they are making visual inspections in areas containing any sharp items such as lancets, syringes, pens, and pump supplies. This will prevent them from receiving an accidental needle puncture. Finally, patients who experience hypoglycemia
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while advancing through the checkpoint should notify the TSA screeners that they are in need of immediate medical assistance.
Patients should consider packing a small medical jump kit whenever they travel. The following items should be included in the jump kit, which is placed in the carry on rather than the checked luggage. This is not only to prevent loss from bags being misplaced but also to protect insulin because baggage stored in cargo holds can be subject to extreme temperature changes that may alter the potency of insulin. The contents of the medical jump kit are as follows:
The primary blood glucose meter plus a backup meter
Extra batteries for the glucose meters
Enough insulin, syringes, lancets, test strips, and pump supplies to last at least 7 days longer than the scheduled trip
Consider traveling with insulin pens rather than vials and syringes easier to use while traveling and are less likely to break
Glucose tablets, glucose gel, glucagons emergency kit, or boxes of raisins for managing hypoglycemia
At least one extra vial of each type of insulin used by the patient
Medical ID bracelet that identifies the patient as having diabetes written in the language of the country to which he or she is traveling. (The bracelet can also say give me sugar in that same language.)
A single-day's worth of all prescribed oral medications the patient is taking (for hypertension, hyperlipidemia, gout, neuropathy, etc.)
Insurance card
Emergency contacts at home
Do not attempt to carry extra sensors with you on the plane, as these need to be refrigerated prior to insertion.
For those patients using exenatide, travel kits that maintain the pens in a cool environment for travel are available for purchase at www.medcooler.com.
Patients who use pramlintide might consider placing their injectable drug into a jerry-rigged insulin pen device. A Novo Pen Junior uses disposable insulin cartridges. Using a needle and syringe, remove the insulin from the cartridge. Then clean the vial thoroughly with a normal saline solution. After flushing the vial three or four times, inject the pramlintide directly into the insulin vial and place the vial into the pen. Add a pen needle, and you now have created your very own pramlintide pen injector. Keep in mind, however, that the FDA, Novo Nordisk, and Amylin Pharmaceuticals do not condone this practice. However, many patients prefer the ease and convenience of the pen device to traveling with extra syringes and vials.
If possible, the patient should also have the name of a physician or specialist the patient may contact if necessary for any emergencies while on
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vacation. Patients traveling outside the United States should carry contact information for diabetes specialists in that country. The International Diabetes Federation Web site (http://www.idf.org/home/index.cfm?node=1) provides links to global regions where patients can obtain information regarding diabetes treatment centers outside of the United States prior to their departure date. The names of English-speaking physicians practicing in foreign countries can also be obtained from the International Association of Medical Assistance to Travelers (http://www.iamat.org/). Patients who experience a medical emergency while traveling should contact the nearest U.S. embassy for assistance.
Adjusting Doses of Insulin for Travel
Frequent blood glucose monitoring, avoidance of alcoholic beverages, and adequate hydration with noncaffeinated beverages are good general rules for safe travel. Caffeine can cause headaches, palpitations, perspiration, and anxiety, all of which are symptoms of hypoglycemia. Insulin pumpers should keep their pump clocks set to their original times while traveling. Patients using multiple daily injections (MDI) should keep their wristwatches set to correspond to the time at their original point of departure to make timing of insulin injections related to mealtimes easier.
The flexibility of insulin pump therapy allows for the safest and most stress-free travel, especially when unexpected travel delays occur. Prior to any long-distance travel, MDI patients should be placed on a basal-bolus regimen consisting of glargine or detemir plus a fast-acting insulin analogue. NPH and regular insulin have such unpredictable rates of absorption that hyperglycemia or hypoglycemia is much more likely to occur.
In general, adjustments to insulin doses are unnecessary if patients are crossing fewer than 5 time zones. Patients on basal-bolus insulin who are using glargine should be advised to maintain their same injection schedule when traveling cross country. For example, a patient from Los Angeles who injects glargine at 10 PM nightly should inject at 7 PM while visiting New York. On return to Los Angeles, the 10 PM dosing resumes.
When traveling west to east, the day becomes shorter and mealtimes may be closer together. Doses of premeal short-acting insulin analogues may need to be slightly lowered if injected within 4 to 5 hours of the previous meal to avoid insulin stacking (see Chapter 5). Patients need to be aware of insulin absorption pharmacokinetics principles and predict how much insulin remains at their previous subcutaneous depot to accurately dose insulin for their next meal.
For travel across more than 5 time zones, patients on basal-bolus insulin may take 50% of their prescribed basal insulin dose prior to landing at their destination and 50% at their bedtime on the first day. Thus, a patient who is taking glargine 50 U daily would give 25 U on landing and 25 U at 10 PM on day 1 and 50 U at 10 PM on day 2. The bolus doses of short-acting insulin analogues
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would remain based on preprandial blood glucose levels and carbohydrate content of each meal.
As a reminder, patients should be advised to stretch their legs and walk around the cabin periodically to avoid developing a deep venous thrombosis on long plane trips.
Pump patients should carry supplies of basal insulin in case their pump malfunctions. Basal insulin can be administered in a dose equivalent to the total daily basal dose. If, for example, the patient's pump basal rate is 1 U per hour, glargine 24 U may be administered once daily until the pump is functioning again. Some patients may wish to take a pump holiday and not use their pumps when on vacation. Reverting back to basal-bolus insulin therapy using glargine plus a NovoLog or lispro pen injector is perfectly acceptable for these patients.
Patients on exenatide or pramlintide may elect to withhold use of the medication while on the plane to avoid the likelihood of hypoglycemia. Once at their destination, the usual doses of these drugs may be continued.
Open insulin vials retain their potency at room temperature for at least 1 month, but in warm climates, insulin should be stored either in a refrigerator or in thermal insulated bags. Exenatide should always be refrigerated.
Extreme temperatures and humidity can also affect glucose meters and test strips. Meters generally perform best within temperature ranges of 59 F to 95 F. High-altitude physical exertion may result in retinal hemorrhages, DKA, and hypoglycemia for patients with T1DM.54 Blood glucose meters are also inaccurate above 10,000 feet. Quality control checks with control solution is the best way to verify that the meter and strips are working together properly. Control solutions are solutions of known glucose concentrations. Every meter has at least one control solution, and some have three levels of control solutions (low, normal, and high) so patients can test the meter at the extremes. Control solution is used with the meter the same way a patient tests a drop of blood. Using control solution on the first strip out of a new vial or package is a great way to ensure the accuracy of results. One should not use strips that are bent, outdated, or damp.
For patients with T2DM, the timing of oral medications is not as critical as that of insulin. If the patient is on twice-daily metformin, a thiazolidinedione (TZD), or sulfonylurea, skipping a dose and having slight hyperglycemia for 6 to 8 hours is preferable to taking two doses too close together and risking hypoglycemia.
Self Blood Glucose Monitoring
SBGM allows patients to evaluate their individual response to lifestyle and pharmacologic interventions and to assess whether short-term glycemic targets are being achieved (see Chapter 7). SBGM can also be used to detect extreme changes in blood glucose levels, including hypoglycemia, hyperglycemia, and DKA. Patients who successfully use SBGM can learn to adjust
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insulin doses, alter activity levels, and learn the correlation of food intake with pharmacologic therapy. For patients using MDI of insulin or pregnant women on insulin, SBGM at least four times daily should be encouraged. The positive correlation between frequent blood glucose testing and A1C levels and reduction in hospital admissions due to DKA is well known for patients with T1DM.55 However, the optimal frequency and timing of SBGM for patients with T2DM is unknown and should be dependent on assisting patients to achieve targeted fasting and postprandial glycemic control56 listed in Table 9-14.
TABLE 9-14 Glycemic and Blood Glucose Targets | ||||||||
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Because the accuracy of SBGM is user dependent, physicians should evaluate each patient's monitoring technique at regular intervals.
Suggestions for proper use of SBGM include the following:
The patient should not use alcohol prior to sampling, as alcohol may dilute the blood specimen and provide an inaccurate reading. Instead, washing hands with soap and water immediately after testing is preferred.
The patient should pick two favorite fingers from each hand and use those fingers exclusively for testing. The patient should sample from the middle of the fingertips not the sides of the finger to minimize pain. Over time, a callus will develop. Sampling from the area of the callus will be painless.
If the glucose result obtained is thought to be in error, the patient should not retest from the same finger but use the other hand to retest.
Although alternative site testing (thigh, forearm, palm of hand) is available on most meters, the most accurate readings remain at the patient's fingertips, especially when hypoglycemia is suspected. The patient should avoid alternative site testing immediately after exercise or eating.57
Summary
Both public health and clinical interventions are needed to stem the tide of obesity and diabetes. Although there is an important emphasis at a public health level on prevention, more than 20 million adults in the United States will seek treatment for diabetes.58 Most of these individuals are overweight or
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obese. If this population is treated without a sustainable lifestyle component, they are likely to gain additional weight, increase their waist circumference, worsen their insulin resistance, become hypertensive, and increase their risk of cardiovascular and microvascular-related mortality. As health deteriorates, more medications are likely to be prescribed in an attempt to intensify therapy and treat patients' metabolic parameters to target. Unfortunately, symptomatic patients often experience a deterioration in their quality of life. They lose confidence and desire to participate in any diabetes self-management programs. As exercise becomes a painful challenge, patients are likely to develop depression, which is exacerbated and prolonged by the physical symptoms of diabetes.59
Strategies and suggestions regarding behavioral interventions should be discussed with patients at each visit. Early intervention using medical nutrition therapy, exercise, and a home blood glucose monitor will have a positive impact on patients' futures. Patients have so many questions and fears about diabetes, yet physicians spend little time discussing their concerns during their regular office visits. Physicians should find something positive to say about each patient at every visit. The clinician should sit down with him or her side by side and explain that Yes, having diabetes is a bummer, but by including you in our diabetes treatment team we can make your life so much better. Let me show you how!
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11. Ciechanowski PS, Katon WJ, Russo JE, Walker EA. The patient-provider relationship: attachment theory and adherence to treatment in diabetes. Am J Psychiatry. 2001;158:29 35.
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