Implications of the Diabetes Control and Complications Trial
- American Diabetes Association
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 the standard treatment group) and another treated intensively (goal: normalization of blood glucose; called the 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. Normalization of glucose values was not achieved in the intensively treated cohort as a group because mean glucose values were ∼40% above normal limits. Nonetheless, over the study period, which averaged 7 years, there was an ∼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.
The American Diabetes Association believes that the study has both statistical and clinical significance. The DCCT is the longest and largest prospective study showing that lowering blood glucose concentration slows or prevents the development of diabetic complications. As such, it has major therapeutic implications for health care providers and their patients. Many questions remain to be answered, but the following conclusions appear warranted:
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A primary treatment goal in type 1 diabetes should be blood glucose control at least equal to that achieved in the intensively treated cohort. This goal may not apply to all patients with type 1 diabetes and must …
