THE DIABETES CONTROL AND COMPLICATIONS TRIAL: WHAT DOES IT TELL US

The Diabetes Control and Complications Trial (DCCT) is a landmark multicenter trial designed to test the proposition that the complications of diabetes mellitus are related to elevation of the plasma glucose concentration. The study design was simple. Two groups of patients were followed long term, one treated conventionally (goal: clinical well-being; called standard treatment group) and another treated intensively (goal: normalization of blood glucose; called intensive treatment group). The intensive treatment group was clearly distinguished from the standard treatment group in terms of glycated hemoglobin levels and capillary blood glucose values throughout the duration of the study. Over the study period, which averaged 7 years, there was a >60% reduction in risk between the intensive treatment group and the standard treatment group in diabetic retinopathy, nephropathy, and neuropathy. The benefit of intensive therapy resulted in a delay in the onset and a major slowing of the progression of these three complications. Finally, the benefits of intensive therapy were seen in all categories of subjects regardless of age, sex, or duration of diabetes.

Are the results of the DCCT achievable for most people with diabetes?  In theory, the answer is yes. However, in the real world, great effort will be required to reproduce the results of the DCCT. It must be recognized that the study group was young, generally healthy, and highly motivated. The professional personnel conducting the study were highly trained endocrinologists and diabetes educators in academic centers who were highly motivated and meticulous in their management of the study subjects. The intensively treated group received far more attention and medical services than are routinely available in clinical practice. In many cases, participants and professionals became "family." Broad implementation of intensive therapy will require expanded health care teams. Importantly, even if the DCCT results are not absolutely achieved, any improvement in blood glucose control has been shown to slow the development and progression of microvascular complications.

What form of intensive treatment is recommended? Improved glucose control in type1 diabetes had beneficial effects whether delivered by multiple daily injections or programmable insulin-infusion pumps. The choice of treatment depends on the wishes of the individual patient and the comfort/competence of the health care team with a given technique.