Patients with type 1 diabetes who closely monitor and control their blood sugar live longer than those who don't, according to new research funded by the National Institutes of Health.
The study, published Jan. 6 in the Journal of the American Medical Association, is the result of a nearly 30-year, two-part, multi-site trial following nearly 1,500 patients with type 1 diabetes. The findings provide physicians and their patients with hard evidence showing that intensively maintaining near-normal blood sugar levels translates into improved overall health outcomes.
"I think anyone who has to have a treatment would want to weigh the risk and benefits," said Dr. David Brillon, a professor of clinical medicine at Weill Cornell Medical College and an author on the study who has led the trial at the medical college since the late 1980s. "It's important to study these long-term outcomes and be able to tell patients, 'Yes, you can use intensive glucose-lowering treatments and try to attain glucose levels that will reduce your risk of mortality.'"
While aggressively controlling blood sugar is the accepted treatment for type 1 diabetics today, it was unclear in the 1980s whether that therapy would be effective in reducing diabetes complications, Dr. Brillon said. Investigators at the time were unsure whether diabetes complications occurred as a result of high blood sugar, or if they were associated with other underlying — perhaps genetic — conditions.
Investigators at Weill Cornell and at 28 other sites in the United States and Canada enrolled 1,441 people between the ages of 13 and 39 with type 1 diabetes for the randomized Diabetes Control and Complications Trial, which began with a feasibility phase in 1983. Half of the patients checked their blood glucose levels daily and administered insulin once or twice a day, while the other half monitored glucose levels four or more times a day, particularly before and after meals and at night. Those in the intensive monitoring group also utilized more advanced insulin delivery protocols administering insulin three or more times a day. In some cases, intensive treatment included pumps, which provide a steady and measured dose of insulin that closely mimics the body’s normal release of the hormone.
The trial prematurely ended in 1993, as researchers found that the patients in the intensive glucose monitoring group had substantially less eye, nerve and kidney disease than their peers in the other group. All patients were advised to follow the intensive blood glucose monitoring, and nearly all enrolled in the Epidemiology of Diabetes Interventions and Complications follow-up study that allowed physicians to monitor their long-term health outcomes.
Investigators found that participants in the intensive monitoring group had a 33 percent lower risk of dying compared to those in the conventional group. While 22 percent of patients died from cardiovascular diseases and 18 percent from acute diabetes complications characterized by dangerously high or low blood glucose, not all deaths were attributable to diabetes.
"If someone with type 1 diabetes is able to attain glucose levels that are closer to the normal range, I think that imparts positive effects for the patient in general," Dr. Brillon said. "In addition to less eye, kidney, nerve and heart disease, these patients come away with a reduction in overall mortality."