Testing and prevention
Screening criteria and preventive strategies are more explicit. The new guidelines recommend diabetes and prediabetes testing for asymptomatic individuals who are overweight and have additional risk factors (e.g., physical inactivity, family history of diabetes, hypertension), regardless of age. As before, all individuals older than 45 should also be screened.
The section of the Recommendations on prevention and delay of type 2 diabetes now includes a table listing interventions (Table 1) and summarizing prevention trial results. Counseling is recommended for patients with impaired glucose tolerance (IGT) or impaired fasting glucose (IFG) to help them achieve the goals established by the multicenter Diabetes Prevention Program (DPP): weight loss 5%-10% of body weight and physical activity equal to 150 minutes weekly of moderate walking.
A more significant change is the addition of pharmacotherapy for prevention. The guidelines recommend that clinicians consider metformin for individuals who are obese, younger than 60 years old, and at very high risk (i.e., both IFG and IGT and at least one other risk factor). Metformin was chosen for its low cost (the drug is available generically), relatively benign side-effect profile, and performance in the DPP.
Approach to treatment
The guidelines now include treatment recommendations—general strategies rather than specific drugs—for type 1 as well as type 2 diabetes. For type 1 diabetes, the emphasis is on the use of multiple injections with a mix of basal and prandial insulin, the latter to match carbohydrate intake, premeal blood glucose, and anticipated activity. Insulin analogs should be considered, particularly if hypoglycemia is a problem.
For type 2 diabetes, the Recommendations stress prompt intervention with metformin, dietary modification, exercise, and the addition of other drugs as needed to achieve and maintain glycemic levels as close to normal as possible. Insulin should be considered early on—even at the time of diagnosis in the presence of marked weight loss or other signs or symptoms of severe hyperglycemia.
Beyond metformin and insulin, the guidelines no longer recommend a sequence or schema for choosing among specific drugs for type 2 diabetes.
The guidelines recognize the utility of continuous monitoring of interstitial glucose to supplement self-monitoring of blood glucose in type 1 diabetes, particularly for patients with hypoglycemia unawareness.
Glycemic goals remain largely unchanged, although the language has been revised. Hemoglobin A1c should in general be kept below 7%; the goal might be more rigorous—as close to normal as possible (<6%)—for selected patients and less stringent for others (e.g., with history of severe hypoglycemia or long-standing diabetes with minimal complications).
[Dr. Kirkman points out that the 2008 Recommendations were issued before release of data from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial that associated intensive glycemic control with increased mortality. She notes that the question remains unsettled and that data from this and other trials should clarify the situation soon. “Until we know more, we aren’t changing anything,” she states.]
The section on hypoglycemia has been expanded to include discussions on prevention and hypoglycemia unawareness. Patients who have had episodes of severe hypoglycemia or who have hypoglycemia unawareness should be counseled to raise glycemic goals sufficiently to avoid further episodes for a period of at least several weeks. The same dysfunctions in counter-regulatory hormone release and autonomic response may both increase risk of and result from hypoglycemia. Such irregularities have been shown to normalize after a period in which hypoglycemia is rigorously avoided.