A higher death rate among diabetes patients treated aggressively to lower their blood sugar prompted the government on Wednesday to halt one part of a major study of diabetes and heart disease.
The 10,251-patient trial, called ACCORD, is the first test of whether lowering blood sugar in patients with type 2 diabetes to levels found in those without the disease will prevent heart attacks and strokes.
Intensive treatment was stopped 18 months early after researchers found 257 deaths, many that were heart-related, among patients who were given intensive treatment compared with 203 among patients on standard treatment.
"Although we have stopped the treatment, we will continue to care for all study participants," says Elizabeth Nabel, director of the National Heart, Lung, and Blood Institute, the study's sponsor. She says ACCORD researchers will continue to study the benefits of aggressive blood pressure and cholesterol-lowering treatment as planned until June 2009.
She cautioned that no diabetes patient should change his treatment without consulting a doctor. About 21 million Americans have diabetes, and 284,000 die of it each year. Most deaths are tied to heart disease, the heart institute says.
The finding calls into question the theory that lowering blood sugar to levels in people without diabetes will not only prevent other complications but also protect the heart, doctors say. It also raised questions among researchers as to whether Avandia may have contributed to the unexpected deaths.
In May, researchers linked Avandia to an increased risk of heart attacks. But the ACCORD team found no such link to any medication. "More (Avandia) was used in the intensive treatment group than in the standard treatment group," says William Friedewald of Columbia University, chairman of the study's steering committee. He adds that "there were no more deaths among those taking (Avandia) than those who were not."
He says researchers are still trying to figure out why the deaths occurred, as there appeared to be a 10% reduction in the risk of non-fatal heart attacks. When heart attacks occurred, Friedewald says, they were more likely to be deadly.
"It's very hard to sort out," says Steven Nissen, who carried out the study linking Avandia to heart attacks. "We've got to be careful not to jump to conclusions."
A separate study in today's New England Journal of Medicine showed that intensive therapy for diabetes may be effective if doctors don't push blood sugar levels quite so low. Researchers in Copenhagen reduced patients' blood sugar levels to 7.9% in the 160-patient study, compared with the 6.4% achieved in ACCORD. The result: a death rate that was 20% lower for patients who were treated aggressively.
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