Chicago, IL—On the 30th anniversary of the landmark Diabetes Control and Complications Trial (DCCT), the results of its 20-year observational Epidemiology of Diabetes Interventions and Complications (EDIC) study showed substantial reductions in the risk of developing severe eye disease, impaired kidney function, heart disease, and stroke with long-term intensive therapy in patients with type 1 diabetes. The results were presented at the 2013 American Diabetes Association annual meeting.
The 10-year results of this landmark government-funded trial showed that intensive therapy achieved near-normal glucose levels and reduced retinopathy by 76%, kidney disease by 50%, and neuropathy by 60%. “On the basis of these results, DCCT intensive therapy has been adopted worldwide as the standard of therapy for type 1 diabetes,” said David M. Nathan, MD, Director of the Massachusetts General Hospital Diabetes Center in Boston. Dr Nathan cochairs the study.
More than 95% of the surviving members of the original 1441 DCCT participants continue to be followed in the observational EDIC study. At the end of the DCCT, patients in the conventional therapy group were switched to intensive therapy.
Greater benefits were seen in the patients who were initially randomized to intensive therapy, according to the EDIC results.
Judith E. Fradkin, MD, Director of the Division of Diabetes, Endocrinology, and Metabolic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, said, “The long-term results of the DCCT/EDIC further reinforce the importance of early intensive therapy over the lifetime of people with type 1 diabetes. Our challenge now is to ensure that all patients with type 1 diabetes are able to take advantage of these remarkable findings and to make intensive therapy as convenient and safe as possible."
During the DCCT, the target hemoglobin (Hb) A1c was <6.5%, and more than 50% of patients reached that goal at least once, said Dr Nathan. The average HbA1c was 7% with intensive therapy and 9% with conventional therapy.
In addition, the EDIC showed that impaired kidney function was reduced by 50% with intensive therapy, according to Ian H. de Boer, MD, MS, Associate Professor of Medicine, University of Washington, Seattle. “The reduction in impaired kidney function represents a major finding since kidney failure increases the risk of subsequent heart disease and death more than any other complications,” Dr de Boer said.
At 8 years after the DCCT, a continued benefit in terms of reduced risk of microalbuminuria and macroalbuminuria was seen in the intensive therapy group, and this benefit was sustained through 20 years with continued separation of the curves between the groups.
Hypertension incidence was approximately 50%, which was reduced by approximately 20% during the first 14 years of EDIC with intensive therapy. The risk of impaired glomerular filtration was also reduced by 50% over the long-term, as first reported in 2011 in the New England Journal of Medicine. Cardiovascular disease was reduced by approximately 50% at 21 years, as first reported in 2005 by Nathan and colleagues (N Engl J Med. 2005;353:2643-2653).
“The risk reduction in the former intensive therapy group has persisted through 2012,” said John M. Lachin, ScD, Professor of Biostatistics and Epidemiology, and of Statistics, George Washington University, Rockville, MD, with the lower HbA1c during the DCCT trial explaining the reduction.
Approximately a 50% reduction was found with intensive therapy for the risk of eye surgery and retinal detachment. An underappreciated condition in diabetes—progressive stiffening around the hands and shoulders—affected 66% of DCCT participants after 30 years of diabetes; however, lower glucose levels were associated with reduced risk of these complications.