Drugs diabetics use to drastically cut blood sugar levels increased deaths from heart disease in one study and reduced kidney illness in another, results that challenge the use of a uniform strategy to treat diabetes.
The two trials, which followed more than 21,000 elderly, often obese diabetics, used multiple drugs to tightly control blood sugar levels to help patients avoid complications that can cause disability and death. While cutting kidney disease in one trial, the treatments failed to protect diabetics from heart disease and stroke in the second.
Both studies, the largest ever for diabetes, were published today by the New England Journal of Medicine.
The conflicted findings call into question the common use of powerful drug combinations to slash the blood sugar of diabetics to levels seen in non-diabetics, said Harlan Krumholz, a Yale University cardiologist who wasn't involved in the studies.
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“The results are surprising and question the conventional wisdom that the lower you get blood sugar, the better off patients are and the lower their risk,” Krumholz said in a telephone interview Friday. “These studies should give us pause” about the current standard of treatment.
An estimated 180 million people around the world have diabetes, according to the Geneva-based World Health Organization, which predicts the number will double by 2030. The blood sugar studies will also be discussed by researchers at the annual meeting of the American Diabetes Association, which began Friday in San Francisco.
More than 90 percent of diabetes patients have the Type 2 form, which occurs when the pancreas doesn't produce enough insulin, a hormone that allows cells to convert glucose, or sugar, into energy.
The first of the two studies published Friday, called the ACCORD trial, was aimed at learning which of two approaches would better protect Type 2 diabetics from developing serious cardiovascular problems. The patients, whose average age was 62, entered the study with an average glucose level of 8.1 percent, about 2 points higher than healthy non-diabetics.
One group in the trial received intensive therapy and multiple drugs aimed at lowering their glucose level to 6 percent or below. Others in the trial received less rigorous treatment that aimed for blood sugar levels that ranged from 7percent to 7.9 percent.
While the intensively treated patients had a slightly lower risk of heart attacks and strokes, patients in that group were more likely to die from such events and from other causes.
The second study, released for the first time Friday, focused on reducing complications involving small blood vessels.
Dubbed the Advance trial, the study found that patients given an intensive regimen that included the drug Diamicron, marketed in Europe by Les Laboratoires Servier, a closely held French company, slashed glucose levels to 6.5percent and cut the number of patients with kidney disease by 21 percent.
The dueling results “do add to confusion because you're seeing different outcomes in groups of patients that are fairly similar,” said Martin Abrahamson, medical director of the Joslin Diabetes Center, a Boston clinic affiliated with Harvard Medical School. While the use of multiple drugs seems to be contributing to good and bad outcomes, trying to push glucose too low may be dangerous, he said.