Drug May Delay or Even Prevent Type 2 Diabetes

A drug widely used to treat Type 2 diabetes delayed or prevented progression of prediabetes to diabetes by 60% in the largest such prevention trial ever conducted, researchers reported Friday.

More than 41 million Americans have blood glucose abnormalities — known as prediabetes — that indicate they may soon develop diabetes, making them good candidates for use of the drug, called rosiglitazone.

There is currently no treatment other than diet and exercise for preventing progression to Type 2 diabetes.

"I think it will change treatment practices if it stands up," said Dr. Andrew Drexler, director of UCLA's Gonda Diabetes Center, who was not involved in the study.

Some physicians, such as Dr. Stuart Weiss of the New York University School of Medicine, have already begun giving rosiglitazone to their pre-diabetic patients.

"Getting people on drugs early is a very important thing," he said. The complications of diabetes, such as heart and kidney disease, "occur even before the diabetes is diagnosed…. We need to be much more aggressive and get in sooner."

The one important side effect of the drug during the three-year study was an increase in congestive heart failure, although the absolute number of cases was low and physicians were able to manage it successfully.

The results with rosiglitazone, which costs as much as $170 per month, are comparable to those achieved with intensive programs to modify diet and increase exercise, but experts noted that few physicians or patients were willing to invest the time and effort necessary for such a treatment program.

The results of the study were presented Friday in Copenhagen at a meeting of the European Assn. for the Study of Diabetes. They will be published in today's issue of the journal Lancet.

In the United States, an estimated 18 million people have Type 2 diabetes, and the number has been growing so rapidly that the Centers for Disease Control and Prevention has declared diabetes an epidemic.

Worldwide, 220 million people have diabetes. Most of them develop heart disease, kidney disease, blindness or nerve damage, often leading to amputation of limbs.

"Anything we can do to prevent it will have huge public health implications," said Dr. Vivian Fonseca of the Tulane University Health Sciences Center.

Unlike Type 1 diabetes, in which the pancreas stops producing insulin completely, Type 2 diabetes occurs when the pancreas loses part of its ability to produce insulin and the body's cells lose part or all of their ability to use insulin to remove glucose from the bloodstream for use by cells.

Rosiglitazone, sold by GlaxoSmithKline under the brand name Avandia, increases the sensitivity of cells to insulin.

Earlier studies on treating diabetes had suggested that rosiglitazone and a second drug, ramipril, might also halt progression to diabetes. Ramipril, sold by King Pharmaceuticals Inc. and Wyeth under the brand name Altace, increases production of insulin.

The current study, led by Dr. Hertzel Gerstein of McMaster University in Ontario, Canada, enrolled 5,269 people with pre-diabetes in 21 countries. All had abnormal readings on either a glucose tolerance test or a fasting glucose test: Their glucose levels in the standard tests were higher than normal, but not high enough to be considered full-blown diabetes.

Previous studies have shown that 29% to 59% of such pre-diabetic patients will progress to diabetes within three years.

The subjects received daily doses of either rosiglitazone, ramipril, a placebo or both drugs. The two drugs were not compared head-to-head, and the results in patients who received both drugs have not yet been reported. All of the subjects also received standard counseling about the importance of dieting and exercise.

Gerstein reported that 10.6% of the 2,365 people who received rosiglitazone progressed to diabetes, compared with 25% of the 2,634 given a placebo. Fourteen of those receiving the drug developed congestive heart failure, compared with two of those receiving placebo.

Rosiglitazone is known to cause a buildup of fluids in some patients, which can lead to heart failure. Weiss noted that this could be controlled or prevented by counseling patients to reduce the amount of salt in their diet.