Diabetes :: Strict blood sugar control cuts diabetes heart risk

A 20-year study of people with type 1 diabetes shows that tight control of blood sugar levels cuts their risk of heart disease by more than half. The new research, published in the Dec. 22 New England Journal of Medicine, is “a landmark study,” according to Dr. William T.

Cefalu, chief of the division of nutrition and chronic diseases at the Louisiana State University Pennington Biomedical Research Center, who also wrote an accompanying editorial.

“It is tremendously difficult to maintain the proper glucose level,” he says. “This study shows that it is important to make the effort.”

The study “fills in what was a major piece of the puzzle concerning diabetes control and complications,” says lead researcher Dr. David Nathan, director of the Diabetes Center at Massachusetts General Hospital in Boston.

The Diabetes Control and Complications Trial, which began in 1983, originally was aimed at showing that “tight control of blood sugar levels would have a major impact on kidney, eye and nerve disease,” Nathan says. “Then it turned to whether tight glucose control would benefit cardiovascular disease, which is the major killer of people with diabetes.”

The answer was a clear “yes.” Following more than 1,400 people with type 1 diabetes for two decades, his team found that those who used aggressive methods to get their measure of blood sugar level to about 7 percent had a 57 percent lower risk of heart attack, stroke or death from cardiovascular disease.

For six years, this subgroup of diabetics was targeted by the study leaders. They had their blood sugar levels monitored closely, and had at least three insulin injections a day, or used an insulin pump in an effort to achieve tighter-than-usual control.

They were then turned over to their own doctors, who used conventional methods to control blood sugar. Even though there may have been some relaxation of supervision, “we still continue to see long-term effects of the original intervention,” Nathan says.

Type 1 diabetes is the less common form of the disease. It typically begins early in life, and is caused by an inability of the body to produce insulin. About 1 million Americans have type 1 diabetes, while an estimated 17 million have type 2, which is often tied to obesity and begins in adult life as the body gradually produces less and less insulin.

Nathan says he is often asked whether tight control of blood sugar will have similar cardiovascular benefits in type 2 diabetes.

“We don’t know,” he says. “There are differences in the patient populations. People with type 2 usually also have hypertension, high blood lipid levels and are overweight. There is no reason why tight control might not have an effect, but we just don’t know now.”

The answer should come from two major studies being funded by the U.S. National Institutes of Health, Nathan says.

Achieving the results of the study in the real world for people with type 1 diabetes will not be easy, he adds. Even with the rigorous efforts made in the study, the researchers fell short of their goal. They aimed for 6 percent and had to settle for 7 percent blood glucose.

“This is hard work for the patients,” Nathan says. “We showed them the road to salvation. The problem is that this is just a road map. In the end, they have to make the trip. And it is a hard trip.”

It is hard work for physicians as well, and a job that the U.S. medical system is not prepared for, Cefalu says.

“It takes a lot of effort, not just on the part of the physician, but also on the team, the nutritionist, the nurse,” he says. “It takes time to educate the patient. The problem is that physicians aren’t paid for their time spent in educating. That should be our priority.”

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