Glucose Control in Type 2 Diabetes Mellitus

The burden of diabetes mellitus is a consequence of the devastating chronic complications of the disease. In the United States, diabetes remains the leading cause of new blindness in adults, end-stage renal disease resulting in dialysis or transplantation, and nontraumatic amputations. Today, however, future blindness, kidney failure, and amputation should be markedly lessened as we implement preventive strategies, including attainment of meticulous glycemic control, laser photocoagulation, and early introduction of therapy with angiotensin-converting enzyme inhibitors.

In patients with type 1 diabetes, the debate over the role of careful glycemic control in the evolution of complications has ended, thanks to the Diabetes Control and Complications Trial (DCCT) [1]. The DCCT is the most important clinical study ever conducted in the field of diabetes. This multicenter randomized, controlled clinical trial showed that intensive treatment of type 1 diabetes, with the goal of meticulous glycemic control, dramatically decreases the frequency and severity of retinopathy, nephropathy, and neuropathy. Yet, the extent to which the DCCT results apply to patients with type 2 diabetes has been questioned. The arguments that it does apply are three.

First, extensive epidemiologic studies (as exemplified by the Wisconsin study [2, 3], with its 10 years of follow-up) have shown a strong and consistent relation between glycemia and the incidence and progression of microvascular (diabetic retinopathy, loss of vision, and nephropathy) and macrovascular (amputation and death from cardiovascular disease) complications in patients with type 1 or type 2 diabetes [2, 3]. The similar outcomes in type 1 and type 2 diabetes suggest that glycemia plays a similar role in both conditions.

Second, the DCCT did not find a “glycemic threshold.” Rather, there was …