Sept. 15, 2006 -- A widely prescribed drug used to treat type 2 diabetes is also highly effective for preventing the disease, researchers reported today at a meeting in Copenhagen, Denmark.
The risk reduction was double that reported with any other drug used for diabetes prevention, and on par with reductions that have been reported in studies examining lifestyle changes alone.
The potentially landmark findings could usher in a new era of diabetes management similar to that already seen with heart disease, where drug therapies prescribed to prevent the disease become as important as those used to treat it, experts said.
Millions at Risk
About 20 million Americans have type 2 diabetes, and millions more are considered to be at high risk for developing the disease. As many as 40% of adults in the U.S. between the ages of 40 and 74 -- or 41 million people -- have prediabetes, according to government estimates, meaning that their ability to process blood sugars, or glucose, is compromised.
The newly reported trial was designed to find out if treatment with Avandia substantially reduced the chances of developing diabetes.
It included 5,269 people treated at 191 clinics around the world. The average age of the study participants was 55 and all had evidence of prediabetes with either impaired fasting glucose (blood sugar) or impaired glucose tolerance. Having prediabetes puts you at high risk for developing type 2 diabetes.
Roughly half were treated with 8 milligrams of Avandia daily and half received placebo. Both groups were also given advice on how to lower their diabetes risk with diet and exercise, but study participants were not required to make lifestyle changes.
After an average three years of treatment, 306 people taking Avandia had developed diabetes or died from any cause; that compares with 686 of the placebo-treated participants. And treatment with the diabetes drug was found to increase the likelihood that participants would revert from prediabetes to a normal blood sugar status by 70% to 80% compared with placebo.
In a related trial involving the same patient population, the blood pressure drug Altace was not found to be effective for the prevention of diabetes. But 43% of the people who took the drug reverted to normal glucose levels by the end of the study, compared with 38% of placebo-treated participants. These results will be published in the upcoming issue of The New England Journal of Medicine.
Gerstein presented findings from both the trials in Copenhagen at the 42nd annual Meeting of the European Association for the Study of Diabetes. The diabetes drug findings were also published in the Sept. 15 issue of the journal The Lancet.
The study was funded by the Canadian Institute of Health Research, in conjunction with the pharmaceutical company GlaxoSmithKline, which markets Avandia, and King Pharmaceuticals, which markets Altace. GlaxoSmithKline is a WebMD sponsor.
Avandia: Not All Good News
Not all the news from the Avandia trial was good, however. Fourteen of the people treated with the drug developed heart failure (0.5%), compared with just two people (0.1%) in the placebo arm of the study.
"Balancing both benefits and risks suggests that for every 1,000 people treated with [Avandia] for three years, about 144 cases of diabeteswill be prevented, with an excess of four to five cases of congestive heart failure," the researchers wrote in The Lancet.
American Diabetes Association president Larry C. Deeb, MD, tells WebMD that the finding means that the drug is not appropriate for all people at high risk for diabetes.
"This probably isn't the drug to use in patients who have multiple risk factors for heart failure, and anyone with any risk factors should be monitored closely while they are on it," he says.
Deeb points out that the reduction in diabetes risk reported by Gerstein and colleagues is almost identical to that seen with modest changes in lifestyle in a major, U.S. government-funded prevention trial.
People who took part in the Diabetes Prevention Program trial were asked to eat less fat and fewer calories and to exercise for 30 minutes a day five days a week. These lifestyle changes resulted in a 58% reduction in risk for getting type 2 diabetes.
"These people weren't asked to drop huge amounts of weight or run 5 miles a day, seven days a week," Deeb says. "They were asked to make modest lifestyle changes, but the risk reductions were dramatic."
While the participants in the Avandia study were also instructed on diet and exercise, it is not clear how many of them changed their eating and exercise habits.
"It is reasonable to think that combining this drug with lifestyle change could result in even greater reductions in diabetes risk, but we can't say this from this study," Deeb says.
In the same government trial, taking the drug metformin (Glucophage), which is already widely used for diabetes prevention, was associated with a 31% reduction in disease risk -- about half that seen in the Avandia study.