On 13 June 1993, the results of the Diabetes Control and Complications Trial were announced during the annual scientific meeting of the American Diabetes Association in Las Vegas, Nevada. After more than a decade of careful planning, much hard work, and perseverance, the results were both clear and dramatic. Intensively managed 13-to 39-yr-old IDDM patients maintained (for 4-9 yr at |50 mg/dl [2.8 mM]) lower mean blood glucose levels than fairly well controlled, conventionally treated patients and had a substantial reduction in the development or progression of retinopathy, nephropathy, and neuropathy as well as a likely reduction in macrovascular complications of diabetes. These benefits outweighed a threefold increase in the risk of severe hypoglycemia and modest excess weight gain observed in intensively managed patients.
As Dr. Oscar Crofford informed the patient volunteers several days before the public announcement of the main DCCT results, the early termination of the trial was only the "end of the beginning." The study describing the main DCCT results has been published . More detailed results of the ocular, renal, neurological, and macrovascular aspects of the trial, and additional reports on treatment implementation, quality of life, neurobehavioral effects, pregnancy, adolescent control, and other issues are being prepared. Most importantly, soon after each of these results are published, the DCCT plans to make most of the data tapes available to qualified scientists for further analysis and discussion in the years to come. Furthermore, it is likely that much will be learned from an anticipated long-term follow-up of the DCCT patients during the next decade. The sera and immortalized lymphocytes and DNA from the DCCT volunteers and their first-degree relatives should prove to be an invaluable resource for further research. The DCCT may very well spawn more original, peer-reviewed scientific studies than any other experiment in the history of diabetes research and may do this before the end of this decade.
In this perspective I share a few of my own initial impressions of the DCCT results. Like other investigators participating in the DCCT, I have not had access to much more data than that presented publicly because the main study results remained masked to the investigators until shortly before they were released to the general public. Furthermore, it should be made clear that these are my own impressions and do not necessarily reflect the opinions of either the DCCT or the American Diabetes Association.
LESSONS IN RETINOPATHY
Before publication of the DCCT results it was known that two factors served as powerful predictors of subsequent retinopathy progression in patients with diabetes: duration of disease and glycosylated hemoglobin concentrations [2-4]. After 15 yr of IDDM, almost everyone develops a mild form of background retinopathy. Among these, a minority progress to more severe forms of clinically significant macular edema or proliferative retinopathy that can impair or threaten vision. Although genetic and other factors, such as hypertension, may influence which patients do or do not develop more severe disease, one thing seems certain: a single measurement of glycosylated hemoglobin predicts...
This is a preview. Get the full text through your school or public library.