Risks and benefits of attaining HbA(1c) goals: examining the evidence.

Type 2 diabetes mellitus (T2DM) is associated with an increased risk of microvascular and macrovascular complications. To manage T2DM, the American Diabetes Association recommends lowering glycated hemoglobin levels to less than 7%, but even lower goals may be possible in patients with low risk of hypoglycemia. Although many studies have demonstrated that aggressive glycemic control has a clear benefit in the reduction of microvascular complications, more data are needed to further characterize the effect on macrovascular complications. Furthermore, researchers must consider the evidence of a "legacy effect," in which benefits do not become evident until years later. The risks of aggressive glycemic control, such as hypoglycemia and weight gain, must be weighed against the benefits in each individual patient.