Tight Control Cuts Diabetes Heart Harm
Intensive Insulin Halves Heart Disease, Death in Type 1 Diabetes
Dec. 21, 2005 -- Tight blood sugar control with insulin slashes the risk of heart disease for people with type 1 diabetes in half, new research shows.
Two-thirds of people with diabetes die of heart attack or stroke. The risk of heart disease is 10 times higher in people with type 1 diabetes than in those without diabetes.
But a landmark study shows that by keeping their blood sugar under tight control, people with type 1 diabetes can reduce their risk of heart attack, stroke, and death from heart disease by 57%. Saul Genuth, MD, of Case Western Reserve University, chaired the study.
"We see a greater reduction in [heart attack, stroke, and death] from intensive blood glucose control than from drugs that lower blood pressure and cholesterol," Genuth says, in a news release. "This therapy should begin as early as possible and be maintained as long as possible."
It's likely that tight blood-sugar control will help people with type 2 diabetes, too. But proof that the benefits outweigh the risks won't arrive until a study of such patients is finished in 2009. Nevertheless, the current report -- in the Dec. 22 issue of the New England Journal of Medicine -- powerfully links high blood sugar to heart disease.
Beginning in 1983, Genuth and colleagues signed up 1,441 type 1 diabetes patients. Half were assigned to what then was normal treatment: daily blood or urine testing for sugar levels, and one or two insulin shots a day.
The other half of patients got intensive treatment. They checked their blood-sugar levels at least four times a day, and took insulin injections three or more times a day or used an insulin pump. Their goal was to keep their HbA1c level -- a measure of average blood sugar over the past two to three months -- at less than 6%.
Over the 6.5-year study, the intensive-treatment group averaged an HbA1c level of 7.4%, while the normal-treatment group averaged 9.1%.
When the first phase of the study ended in 1993, normal-treatment patients were offered intensive treatment. Over the next decade, their HbA1c levels dropped. During that same time, the average HbA1c level for the original intensive-treatment group went up. Soon, both groups had the same HbA1c level.