Intensive glycemic control and the prevention of cardiovascular events: implications of the ACCORD, ADVANCE, and VA Diabetes Trials: a position statement of the American Diabetes Association and a Scientific Statement of the American College of Cardiology Foundation and the American Heart Association.

Diabetes is defined by its association with hyperglycemiaspecific microvascular complications; however, it also imparts a 2to 4-fold risk of cardiovascular disease (CVD). Although microvascular complications can lead to significant morbidity and premature mortality, by far the greatest cause of death in people with diabetes is CVD. Results from randomized controlled trials have demonstrated conclusively that the risk of microvascular complications can be reduced by intensive glycemic control in patients with type 11,2 and type 2 diabetes.3–5 In the Diabetes Control and Complications Trial (DCCT), there was an 60% reduction in the development or progression of diabetic retinopathy, nephropathy, and neuropathy between the intensively treated group (goal A1c, 6.05%; mean achieved A1c, 7%) and the standard group (A1c, 9%) over an average of 6.5 years. The relationship between glucose control (as reflected by the mean on-study A1c value) and risk of complications was log-linear and extended down to the normal A1c range ( 6%) with no threshold noted. In the UK Prospective Diabetes Study (UKPDS), participants newly diagnosed with type 2 diabetes were followed up for 10 years, and intensive control (median A1c, 7.0%) was found to reduce the overall microvascular complication rate by 25% compared with conventional treatment (median A1c, 7.9%). Here, too, secondary analyses showed a continuous relationship between the risk of microvascular complications and glycemia extending into the normal range of A1c, with no glycemic threshold.