NIH News Release
National Institute of Diabetes
and Digestive and Kidney Diseases

Wednesday, February 9, 2000
5:00 p.m. EST
Joan Chamberlain (301) 496-3583

Sue McGreevey (617) 724-2764
Massachusetts General Hospital

George Stamatis (216) 368-3635
Case Western Reserve University

Benefits of Tight Blood Sugar Control Endure for Years

People with diabetes who intensively manage their blood sugar experience long-lasting benefits, researchers have found. For people with type 1 diabetes who participated in the Diabetes Control and Complications Trial (DCCT), the benefits of intensive blood sugar control at reducing diabetic complications persisted for 4 years after the trial ended. These were the findings of a DCCT follow-up study, called Epidemiology of Diabetes Interventions and Complications (EDIC), published Feb. 10 in The New England Journal of Medicine.

The DCCT, a multicenter study of 1,441 people with type 1 diabetes, compared intensive treatment with conventional treatment. Patients on intensive treatment kept glucose levels as close to normal as possible with at least three insulin injections a day or an insulin pump, and frequent self-monitoring of blood glucose. Intensive treatment aimed to keep hemoglobin A1c (HbA1c), which reflects average blood glucose over a 2- to 3-month period, as close to normal (6 percent) as possible. Conventional treatment consisted of one or two insulin injections a day with once-a-day urine or blood glucose testing.

After an average of 6.5 years, HbA1c levels averaged 7.2 in the intensive and 9.1 in the conventional treatment groups. DCCT results showed that the intensive control group had greatly reduced diabetic eye, nerve, and kidney disease compared to conventional therapy. When the DCCT ended in 1993, subjects who had received conventional treatment were taught intensive treatment, and all participants were encouraged to use intensive treatment. Participants then returned to the health care system.

The striking new finding is that people who received intensive therapy during DCCT continued to have a lower risk of eye and kidney disease than those who had been on conventional treatment, even though both groups' HbA1c values leveled off at about 8 percent during 1994 to 1998, the first 4 years of EDIC.

"Intensive management, with the aim of keeping blood glucose levels as close to normal as possible, is extremely effective at reducing the complications of diabetes," said Dr. David Nathan of Massachusetts General Hospital, who co-chaired the DCCT/EDIC research group. "Now we know that the benefits of intensive control continue for years. The take-home message is that the earlier intensive therapy begins and the longer it can be maintained, the better the chances of reducing the debilitating complications of diabetes."

"This new understanding would not have been possible without the dedication of the DCCT/EDIC volunteers, who have been real research partners. All of them and all diabetic patients should benefit by practicing intensive diabetes treatment," commented Dr. Saul Genuth, study chair, of the Case Western Reserve University.

"A significant body of scientific evidence shows the importance of intensive blood sugar control not only in type 1 but also in type 2 diabetes," added Dr. Allen Spiegel, director of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) of the National Institutes of Health. "Intensive control is a difficult regimen to follow, but the EDIC findings reveal that its benefits are even greater than we realized in preventing the painful, debilitating, and costly complications of diabetes."

About 16 million people in the United States have diabetes, the most common cause of blindness, kidney failure, and amputations in adults. About 10 percent, or 1.6 million, have type 1 diabetes. Formerly known as juvenile onset diabetes or insulin-dependent diabetes, type 1 diabetes usually occurs in children and adults under age 30. It develops when the body's immune system attacks the insulin-producing cells of the pancreas.

Type 2 diabetes, which accounts for about 90 percent of diabetes in the United States, is most common in adults over age 40. It usually is due to a combination of insulin resistance, a disorder in which the cells do not use insulin properly, and the inability of the pancreas to secrete adequate insulin. Type 2 diabetes is associated with obesity, inactivity, family history of diabetes, and race/ethnicity. African Americans, Hispanic/Latino Americans, American Indians, and some Asian Americans and Pacific Islanders are at particularly high risk for type 2 diabetes.

DCCT and EDIC were supported by the NIDDK, the National Center for Research Resources at the NIH, and by Genentech through a Cooperative Research and Development Agreement with the NIDDK.