Diabetes requires continuing medical care and patient self-management to prevent acute complications and to reduce the risk of long-term complications. Diabetes care is complex and requires that many issues—not only glycemic control—be managed. To address these issues, the American Diabetes Association (ADA) published a position statement containing evidence-based recommendations for diabetes care, treatment goals, and tools to evaluate the quality of care. The full statement, “Standards of Medical Care in Diabetes—2006,” was published in the January 2006 supplement to Diabetes Care.
Type 2 diabetes usually is not diagnosed until complications develop, and approximately one third of all persons with diabetes may be undiagnosed. Screening to detect prediabetes should be considered in persons 45 years and older, particularly in persons with a body mass index (BMI) of at least 25 kg per m2. Screening also should be considered in persons who are younger than 45 years if they are overweight and have an additional risk factor (Table 1). Screening for prediabetes and diabetes should be performed in high-risk, asymptomatic children (Table 2) and adults. If test results are normal, repeat testing should be performed at three-year intervals in adults and at two-year intervals in children.
|Testing should be considered in all persons 45 years and older, particularly in persons with a BMI of 25 kg per m2 or greater. If test results are normal, testing should be repeated at three-year intervals.
|Testing should be considered in younger persons and performed more frequently in persons with a BMI of 25 kg per m2 or greater who have additional risk factors, such as those who:
|Are habitually physically inactive
|Are members of a high-risk ethnic population (e.g., Hispanics, blacks, Native Americans, Asian Americans, Pacific islanders)
|Have a first-degree relative with diabetes
|Have a high-density lipoprotein cholesterol level of less than 35 mg per dL (0.90 mmol per L) or a triglyceride level of more than 250 mg per dL (2.82 mmol per L)
|Have a history of vascular disease
|Have been diagnosed with gestational diabetes
|Have delivered an infant weighing more than 9 lb (4.1 kg)
|Have hypertension (blood pressure of 140/90 mm Hg or greater)
|Had impaired glucose tolerance or impaired fasting glucose levels on previous testing
|Have polycystic ovary syndrome
|Have other clinical considerations associated with insulin resistance (e.g., acanthosis nigricans)
|Overweight (body mass index greater than 85th percentile for age and sex, weight greater than 85th percentile for height, or weight more than 120 percent of ideal for height)
|Plus any two of the following risk factors:
|Family history of type 2 diabetes in a first- or second- degree relative
|High-risk ethnic population (e.g., Hispanic, black, Native American, Asian American, Pacific islander)
|Maternal history of diabetes or gestational diabetes
|Signs of insulin resistance or conditions associated with insulin resistance (e.g., acanthosis nigricans, hypertension, dyslipidemia, polycystic ovary syndrome)
|Clinical judgment should be used to test for diabetes in high-risk patients who do not meet these criteria.
|Age of initiation: 10 years (or onset of puberty, if puberty occurs at a younger age)
|Frequency: every two years
|Test: fasting plasma glucose (preferred)
The two-hour oral glucose tolerance test (OGTT) identifies persons with impaired glucose tolerance levels, and thus, more persons who are at increased risk for developing diabetes and cardiovascular disease. Although the effectiveness of interventions for primary prevention of type 2 diabetes has been proven in persons with impaired glucose tolerance, data for persons with impaired fasting glucose levels (who do not also have impaired glucose tolerance) are not available. The fasting plasma glucose test is more convenient for patients, more reproducible, less costly, and easier to administer than the two-hour OGTT; therefore, the fasting plasma glucose test is recommended as the initial screening test for nonpregnant adults.
Once a patient has been diagnosed with diabetes, a complete medical evaluation should be performed to classify the patient, detect any complications, formulate a management plan, and provide a basis for continuing care. The management plan should recognize that diabetes self-management education is an integral component of care. In developing the plan, the patient’s age, school or work schedule and conditions, physical activity level, eating patterns, social situation and personality, cultural factors, and comorbid conditions should be considered.
Glycemic control is best judged by the combination of results of blood glucose self-monitoring and A1C testing. Blood glucose self-monitoring allows patients to evaluate their individual response to therapy and assess whether glycemic targets are being achieved. Patients taking multiple insulin injections should perform blood glucose self-monitoring at least three times daily to monitor for and prevent asymptomatic hypo- and hyperglycemia. Patients who take less frequent injections and those who take oral agents or use nutrition therapy should monitor their blood glucose levels to help achieve glycemic goals. Physicians should routinely evaluate patients’ technique and instruct them on how to use testing data to adjust their therapy.
To assess treatment effectiveness, the A1C test should be performed at least twice per year in patients who are meeting treatment goals and who have stable glycemic control. Patients whose therapy has changed and those who are not meeting treatment goals should be tested quarterly. Conditions that affect erythrocyte turnover (e.g., hemolysis, blood loss) and hemoglobin variants must be considered, especially when the A1C result does not correlate with the patient’s clinical situation.
BLOOD PRESSURE CONTROL
Blood pressure should be measured at every routine visit. Patients with systolic blood pressure of at least 130 mm Hg or diastolic blood pressure of at least 80 mm Hg should have blood pressure confirmed on a separate day. Patients with hypertension (i.e., systolic blood pressure of 140 mm Hg or diastolic blood pressure of 90 mm Hg) should receive drug therapy in addition to lifestyle and behavioral therapy. Multiple agents generally are required to achieve blood pressure targets. Patients with a systolic blood pressure of 130 to 139 mm Hg or a diastolic blood pressure of 80 to 89 mm Hg should receive lifestyle and behavioral therapy alone for a maximum of three months; if targets are not achieved, they should be treated with pharmacologic agents that block the renin-angiotensin system.
Initial drug therapy for patients with a blood pressure of 140/90 mm Hg should include a drug class proven to reduce cardiovascular events in patients with diabetes (i.e., angiotensin-converting enzyme [ACE] inhibitors, angiotensin receptor blockers [ARBs], beta blockers, diuretics, and calcium channel blockers). Patients with diabetes and hypertension should be treated with a regimen that includes either an ACE inhibitor or an ARB. If one class is not tolerated, the other should be substituted. A thiazide diuretic may be added if needed to achieve blood pressure targets.
Adult patients should be tested for lipid disorders at least annually. In adults with low-risk lipid values, assessments may be repeated every two years. Lifestyle modification focusing on the reduction of saturated fat and cholesterol intake, weight loss (if indicated), and increased physical activity has been shown to improve the lipid profile in patients with diabetes. In persons without overt cardiovascular disease, the primary goal is a low-density lipoprotein (LDL) cholesterol level of less than 100 mg per dL (2.60 mmol per L). For persons older than 40 years, statin therapy to achieve an LDL reduction of 30 to 40 percent, regardless of baseline LDL levels, is recommended. Persons younger than 40 years but at increased risk because of other cardiovascular risk factors who do not achieve lipid goals with lifestyle modifications alone should receive pharmacologic therapy.
All patients with overt cardiovascular disease should be treated with a statin to achieve an LDL reduction of 30 to 40 percent. A lower LDL cholesterol goal of 70 mg per dL (1.80 mmol per L), using a high dose of a statin, is an option. Triglyceride levels should be less than 150 mg per dL (1.70 mmol per L), and high-density lipoprotein (HDL) cholesterol levels should be greater than 40 mg per dL (1.05 mmol per L). Combination therapy using statins and other lipid-lowering agents may be necessary to achieve lipid targets but has not been evaluated in outcomes studies for cardiovascular event reduction or safety.
MEDICAL NUTRITION THERAPY
Persons with diabetes should receive individualized medical nutrition therapy to achieve treatment goals. Prevention and treatment of chronic complications of diabetes can be achieved by attaining optimal blood glucose, A1C, LDL, HDL, and triglyceride levels, and optimal blood pressure and body weight (Table 3). Because of the complexity of nutrition issues, a registered dietitian who is skilled in implementing nutrition therapy in patients with diabetes should be part of the medical team.
|A1C level less than 7 percent*
|Blood pressure less than 130/80 mm Hg
|Peak postprandial capillary plasma glucose level less than 180 mg per dL (10 mmol per L)†
|Preprandial capillary plasma glucose level 90 to 130 mg per dL (5.0 to 7.2 mmol per L)
|HDL cholesterol level greater than 40 mg per dL (1.05 mmol per L)§
|LDL cholesterol level less than 100 mg per dL (2.60 mmol per L)
|Triglyceride level less than 150 mg per dL (1.70 mmol per L)
|Key concepts in setting glycemic goals
|A1C is the primary target for glycemic control.
|Certain populations (e.g., children, pregnant women, elderly persons) require special considerations.
|Goals should be individualized.
|Less intensive glycemic goals may be indicated in persons with severe or frequent hypoglycemia.
|More stringent glycemic goals (i.e., normal A1C level of less than 6 percent) may further reduce complications at the cost of increased risk of hypoglycemia.
|Postprandial glucose levels may be targeted if A1C goals are not met despite reaching preprandial glucose goals.
Monitoring total grams of carbohydrate, whether by use of exchanges or carbohydrate counting, is a key strategy in achieving glycemic control. The use of the glycemic index may provide additional benefit. Low-carbohydrate diets (i.e., total carbohydrate intake of less than 130 g per day) are not recommended for persons with diabetes. To reduce the risk of nephropathy, protein intake should be limited to 0.8 g per kg in patients with any degree of chronic kidney disease. Saturated fat intake should be limited to less than 7 percent of total calories, and intake oftrans fat should be minimized. Nonnutritive sweeteners are safe when consumed within the acceptable daily intake levels established by the U.S. Food and Drug Administration. Alcohol intake should be limited to one drink per day for women and two drinks per day for men.
Routine antioxidant supplementation is not advised because of concerns about effectiveness and long-term safety. Chromium supplementation has not been proven to benefit patients with diabetes and is not recommended.
Overweight and obesity are strongly linked to the development of type 2 diabetes and can complicate its management. Obesity also is an independent risk factor for hypertension, dyslipidemia, and cardiovascular disease, which is the major cause of death in persons with diabetes. Patents with a BMI of at least 25 kg per m2 and who have diabetes or are at risk of developing diabetes should be counseled to lose weight. The primary approach should be lifestyle change, which includes a reduction in energy intake and an increase in physical activity. A moderate decrease in caloric balance (i.e., 500 to 1,000 kcal per day) will result in a slow but progressive weight loss of 1 to 2 lb (2.2. to 4.4 kg) per week. For most patients, weight-loss diets should supply at least 1,000 to 1,200 kcal per day for women and 1,200 to 1,600 kcal per day for men.
Physical activity recommendations should be personalized based on the patient’s willingness and ability to increase his or her activity level; the duration and frequency should be increased gradually. At least 150 minutes per week of moderate-intensity physical activity may improve glycemic control and reduce the risk of cardiovascular disease.
Persons with diabetes should receive self-management education according to national standards when their diabetes is diagnosed and as needed afterward. Education should address psychosocial issues, because emotional well-being is strongly associated with positive outcomes. Self-management education helps patients optimize metabolic control, prevent and manage complications of diabetes, and maximize their quality of life.