Hearts don't gain if blood sugar is leashed

Two large studies involving more than 21,000 people found that those with Type 2 diabetes experienced no reduction in their risk of heart attacks and strokes and no reduction in their death rates if they rigorously controlled their blood-sugar levels.

The results bolster findings reported in February, when one of the studies, by the National Institutes of Health, ended prematurely. At that time, researchers made the surprising announcement that study participants who were rigorously controlling their blood sugar actually had a higher death rate than those whose blood sugar control was less stringent.

Now the federal researchers are publishing detailed data from that study. Researchers in the second study, from Australia and involving participants from 20 countries, are also publishing their results on blood sugar and cardiovascular disease. That study did not find an increase in deaths, but neither did it find any protection from cardiovascular disease with rigorous blood-sugar control.Thus both studies failed to confirm a dearly held hypothesis that people with Type 2 diabetes could be protected from cardiovascular disease if they strictly controlled their blood sugar.

Changing behavior

It was a hypothesis that seemed almost obvious. Cardiovascular disease accounts for 65 percent of deaths among people with Type 2 diabetes. And because diabetes is characterized by high levels of blood sugar, the hope was that if people with diabetes could just get their blood sugar as close to normal as possible, their cardiovascular disease rate would be nearly normal as well.

Diabetes researchers say the message is that patients should obtain at least moderate control of blood sugar to protect against eye, kidney and nerve disease. But for heart disease, they say, the only proven method of preventing complications is to give statins to control cholesterol, drugs to control blood pressure and aspirin to control blood clotting, and encourage people to lose weight and exercise.

The Australian study did find one advantage to strict blood-sugar control—a slight reduction in new or worsening kidney disease. The rate among those with intense sugar control was 4.1 percent as compared with 5.2 percent among those with less intense control.

That study got its major support from French drug manufacturer Servier. The company had no influence on the conduct of the study or the analysis or publication of its results, said Stephen MacMahon, a principal investigator and professor of cardiovascular medicine and epidemiology at the University of Sydney.