Identification and treatment of prediabetes to prevent progression to type 2 diabetes.

Overt type 2 diabetes is usually preceded by a condition known as prediabetes, which is characterized by impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). Both IFG and IGT exhibit elevated glucose levels that are not sufficient to be classified as diabetes but that represent the development of insulin resistance. Achieving glycemic control in patients with prediabetes through lifestyle and pharmacologic interventions can effectively prevent or delay the development of diabetes and its associated complications. The first step, however, is to identify patients at risk. Although patients can be identified with an oral glucose tolerance test (OGTT) or a fasting plasma glucose (FPG) screening, a normal FPG does not preclude an elevated OGTT and, therefore, the presence of prediabetes. For patients who progress to type 2 diabetes, intensive therapy aimed at reducing and maintaining glycosylated hemoglobin (A1C) levels < 7% has been shown to reduce the risk of complications. An A1C level > or = 7% should signal the need to initiate or change therapy to achieve glycemic goals.