An Insight into the Recent Diabetes Trials: What is the Best Approach to Prevent Macrovascular and Microvascular Complications?

Type 2 diabetes mellitus (T2DM) accounts for 90%-95% of all diabetes cases. The overarching goal in caring for patients with T2DM is to prevent microvascular and macrovascular complications with glycemic control. Several studies such as UKPDS, DCCT, and EDIC have been performed to evaluate the effects of glucose control on tissue complications in patients with diabetes. In recent diabetes trials including ACCORD, ADVANCE, VADT, BARI 2D, and ORIGIN, intensive glucose control did not prevent macrovascular complications in older patients with long-standing diabetes with either cardiovascular disease or risk factors for cardiovascular disease. In fact, intensive therapy was associated with increased mortality in the ACCORD trial. Although no clear macrovascular benefit was seen in these trials, analyses of earlier studies in younger patients with type 1 and type 2 diabetes have suggested a significant benefit of intensive glycemic control in patients with a shorter duration of diabetes and less vasculopathy. In the UKPDS, the incidence of microvascular disease, particularly retinopathy, was reduced significantly with intensive glucose control, but in the more recent trials (ACCORD, ADVANCE, VADT, ORIGIN) the benefit was relatively modest and limited to reduced proteinuria. Perhaps the most important message from the above trials is to optimize control of cardiovascular risk factors. Although the goal HbA1c to prevent microvascular and macrovascular complications, per the American Diabetes Association, is less than 7%, hypoglycemia should be avoided as it can increase the risk for severe cardiovascular events.