For many years, the goal of drug therapy for most patients with type 2 diabetes has been to achieve and maintain an A1C of <7%. Achieving that goal can prevent microvascular complications (diabetic retinopathy, nephropathy, neuropathy), but whether it prevents macrovascular complications (myocardial infarction [MI], stroke) has been less clear. The FDA now requires that cardiovascular safety studies be performed for all new drugs for type 2 diabetes.1 Recent findings that some of the newer second-line drugs for type 2 diabetes have cardiovascular benefits have led to new interest in the cardiovascular efficacy and safety of all antidiabetic drugs.

The oral biguanide metformin (Glucophage, and others) is generally the drug of choice for initial treatment of type 2 diabetes. It has also been used to prevent or at least delay the onset of diabetes in patients considered to be at high risk for the disease. Recent guidelines recommend considering use of metformin in patients with prediabetes (fasting plasma glucose 100-125 mg/dL, 2-hr post-load glucose 140-199 mg/dL, or A1C 5.7-6.4%), especially in those who are <60 years old, have a BMI >35 kg/m², or have a history of gestational diabetes. Metformin has not been approved for such use by the FDA.