Background
Diabetes is the seventh leading cause of death in the United States and affects nearly 26 million Americans, including up to 27% of adults over age 65. Clinical guidelines aimed at improving the care of adults with diabetes were released by the American College of Physicians and American Diabetes Association early this year. Here is a look at the recommendations for the treatment of type 2 diabetes, by far the most common form in adults.
Conclusions
There are currently 11 unique classes of medications available in the United States for treatment of hyperglycemia in diabetic patients, in addition to several different insulins and insulin analogues.
Most patients with diabetes are treated with multiple medications for blood glucose control; over half take oral medications only, and 14% take insulin in combination with oral medications.
Most oral diabetes medications, when used alone, result in a similar (approximately 1%) degree of hemoglobin A1c reduction. Addition of a second agent – that is, dual therapy – typically reduces HbA1c by an additional 1%.
There are no data on the best time to add oral medications to lifestyle modification for the treatment of type 2 diabetes; there is a similar dearth of data regarding when insulin treatment should be initiated.
Metformin causes more gastrointestinal adverse effects than other oral hypoglycemic medications and is contraindicated in renal insufficiency; but its low cost, beneficial weight effects, and positive impact on most lipid fractions make it the preferred initial agent in most patients.
Thiazolidinediones are associated with an increased risk for incident heart failure.
High-quality evidence shows that sulfonylurea treatment carries a higher risk for hypoglycemia than either metformin or thiazolidinediones.
Implementation
Nonpharmacologic lifestyle interventions (including dietary change, regular aerobic exercise, weight loss and/or control, and abstinence from smoking) are important components that should be incorporated into the management program for nearly every adult patient with diabetes.
When lifestyle changes result in insufficient glucose control, reflected by HbA1c levels above the patient’s goal, oral pharmacologic treatment with metformin should be added.
When metformin plus lifestyle change is insufficient to achieve glycemic control, a second agent should be added. There are data demonstrating that metformin combinations are more effective than other combinations of two oral medications in achieving improved glucose control.
Combination treatments for glucose control are associated with increased adverse events compared with monotherapy. The combination of metformin plus a sulfonylurea has approximately six times the risk for hypoglycemia than the combination of metformin with a thiazolidinedione.
Patients with persistently high glucose despite lifestyle change and oral agents likely need insulin treatment; however, there are no clear data to guide this decision.
A target HbA1c of less than 7% is recommended for most patients with diabetes mellitus; however, this goal is not appropriate for everyone. Setting a glycemic control goal for an individual patient should integrate that person’s risk for complications from diabetes, life expectancy, risk for hypoglycemia with treatment, and patient preferences.
Evidence supports glucose self-monitoring in patients in whom strict glycemic control is the goal, and in those treated with continuous insulin infusion or multiple insulin injections. Self-monitoring should be considered in patients using medications that carry a moderate or greater risk of hypoglycemia, and may be helpful in other selected patients.
Aspirin should be prescribed in patients with a 10-year cardiovascular risk greater than 10%; but the risk of bleeding likely exceeds the potential benefit in patients at lower risk.
Blood pressure should be controlled to levels less than 130/80 mm Hg, and pharmacologic treatment, if needed, should include an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin-receptor blocker (ARB).
Lipids should be controlled in diabetic adults with a low-density lipoprotein target of less than 100 mg/dL; the goal should be tightened to LDL less than 70 mg/dL in those with known coronary and/or vascular disease. Patients with known coronary disease and/or at high risk should be treated with a statin regardless of the level of LDL.
ACE inhibitors, ARBs, statins, and most oral hypoglycemic agents should not be used in women who are likely to become pregnant, as they pose a significant risk to the developing fetus.
Reference
Qaseem, A., et al. Oral Pharmacologic Treatment of Type 2 Diabetes Mellitus: A Clinical Practice Guideline from the American College of Physicians (Ann. Intern. Med. 2012; 156: 218-31).