Self-monitoring of blood glucose is an integral component of diabetes therapy and should always be included in the management plan (SOR:C).
Medical nutrition therapy should be individualized, preferably by a registered dietitian familiar with diabetes (SOR:B).
A regular physical activity program is recommended for all patients with diabetes who are capable of participating (SOR:B).
When a monotherapy fails, combine drugs with different mechanisms of action to achieve an additive effect (SOR:A).
The combination of sulfonylurea and metformin has proven effective in many studies. One showed that initial treatment with glyburide/metformin improved glycemic control better than either glyburide or metformin monotherapy (SOR: A).
Glycemic control in diabetes begins with a patient’s adherence to several nonpharmacologic measures. Without such a commitment, success in controlling the disease will be difficult to achieve, and otherwise appropriate drug therapy will be hindered.
Most antidiabetic agents comparably reduce glycosylated hemoglobin (A1c) levels. However, a particular agent may be preferred depending on a patient’s characteristics. And some circumstances call for combination therapy. This article reviews the advantages and disadvantages of the many pharmacologic treatments for glucose control and hyperglycemia in type 2 diabetes.
Benefits Of Diabetes Control
The benefits of diabetes control are detailed in this issue of THE JOURNAL OF FAMILY PRACTICE (“Strategies to reduce complications in type 2 diabetes,” pages 366–374). For every percentage-point reduction in hemoglobin A1c, it is possible to achieve a 22% to 35% reduction in microvascular complications.1,2 Cardiovascular disease can be reduced in patients with diabetes by treating hypertension3,4 and hyperlipidemia, prescribing aspirin therapy, using angiotensin-converting enzyme (ACE) inhibitors, and with smoking cessation.5,6
Targets For Glycemic Control
The American Diabetes Association’s (ADA) recommended targets for glycemic control are a preprandial blood glucose level of 80–120 mg/dL, a bedtime blood glucose level of 100–140 mg/dL, and a hemoglobin A1c level of <7% (with a level of >8% requiring additional measures). Hemoglobin A1c is the best determinant of glycemic exposure, and its mean value is a nationally recognized indicator of how well diabetes is being managed.7 The American College of Endocrinology has adopted a more aggressive approach by designating an A1c level of 6.5% as both a target and action level.8
Self-monitoring of blood glucose
Self-monitoring of blood glucose (SMBG) is an integral component of diabetes therapy (strength of recommendation [SOR]: C) and should always be included in the management plan (SOR: C). The optimal frequency and timing of SMBG for type 2 diabetes is not known, but they should be sufficient to facilitate reaching glucose goals. The A1c test should be performed at least semi-annually for patients with stable glycemic control, and quarterly for patients not meeting glycemic goals or those who are changing therapy. A1c levels and mean plasma glucose levels can be approximately correlated (Table 1).7
TABLE 1 Correlation between hemoglobin A1clevels and mean plasma glucose levels
Hemoglobin A1c(%)
Mean plasma glucose (mg/dL)
6
135
7
170
8
205
9
240
10
275
11
310
12
345
Nonpharmacologic Therapy
Nonpharmacologic measures remain the cornerstone of managing type 2 diabetes. Hyperglycemia adversely and reversibly affects both insulin resistance and insulin secretion. Improvement in glycemic control can occur through dietary modification and regular exercise.
A recent meta-analysis of randomized controlled trials of diabetes patient education observed a net decrease in HbA1c of 0.32% in intervention groups vs control.9 Interventions that included a face-to-face delivery, cognitive reframing teaching method, and exercise content were more likely to improve glycemic control.
Education
Lifestyle changes involving diet, exercise, and usually weight loss are key to effective management of diabetes. If patients are to change their behavior, they must be given detailed training.6 Self-management also necessitates that patients engage in problem solving. This requires that each aspect of the management plan is understood and agreed upon by the patient and providers, and that the goals and treatment plan are individualized and reasonable.
Diet: recommend soluble fiber, reduce calories
Medical nutrition therapy should be individualized and preferably provided by a registered dietitian familiar with diabetes (SOR: B). The goals of nutrition therapy, according to the ADA, are to attain recommended body weight and prevent or reverse obesity. The means of achieving these goals are nutrition assessment and modification of nutrient intake and lifestyle through healthy food choices and physical activity.7
A high intake of dietary fiber (particularly the soluble type) above the level recommended by the ADA improves glycemic control, decreases hyperinsulinemia, and lowers plasma lipid concentrations.10
Hypocaloric diets cause glucose plasma levels to fall, in some cases to a normal level with a weight loss of even 5 to 10 pounds.7,11 Hypoglycemic medications are of course most effective in nonobese persons. But effectiveness is also improved if weight that is gained can be limited. Despite the clear benefit of weight loss, only a few patients are able to attain and maintain substantial weight loss. Maintenance of a reduced or elevated body weight is associated with compensatory changes in energy expenditure, which oppose the maintenance of body weight that is different from the usual weight.13 Part of the individualization of therapy is respect of personal and cultural preferences, lifestyles, and financial considerations.
