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April 26, 2007 -- Drugs used to treat diabetes are increasingly being prescribed to prevent the disease, but the strategy is being questioned by some.
Writing in the latest issue of BMJ, three diabetes researchers argue that the drug Avandia and other diabetes drugs should not be used for disease prevention because the long-term benefits of such treatments are not known.
Avandia was found to lower type 2 diabetes risk by 62% among people at high risk for developing the disease in a large, international trial reported last fall.
The risk reduction was double that reported with any other drug used for diabetes prevention and on par with reductions reported for lifestyle change.
But it is not yet clear if this benefit translates into a lower risk for common diabetes-related complications -- like heart disease, kidney failure, and blindness -- says Mayo Clinic endocrinologist Victor Montori, MD, ScD.
He tells WebMD that because there is a clear cost and potential risk for harm, the threshold for using drugs to lower diabetes risk must remain very high.
"Prescribing pills to prevent has the effect of converting people into patients," he says. "You transform essentially healthy people concerned about their health into patients who require regular doctor visits and laboratory tests to monitor the drugs they are on."
About 20 million Americans have diabetes, and millions more are considered to have a high risk of developing the disease. According to the American Diabetes Association, as many as 54 million Americans are believed to have prediabetes, meaning that blood sugar, or glucose, levels are elevated but not high enough to be diabetes.
Avandia and a similar drug, Actos, lower blood sugar by helping the body use its natural insulin better. Insulin is a hormone in the body that is necessary to keep blood sugar in check.
But research suggests that this benefit lasts only as long as people remain on the drugs, American Diabetes Association President Larry C. Deeb, MD, tells WebMD.
Deeb says it is clear that drugs are less effective than lifestyle changes for preventing diabetes and diabetes-related complications.
"Regular exercise and a healthy lifestyle benefit patients in many more ways than preventing diabetes," he says. "The benefits in terms of bones and cardiovascular health are much more than you could ever get from a pill."
But he adds that drugs are often the only preventive strategy doctors have to offer when patients don't make the lifestyle changes they need to make.
"Physicians are trained to help patients, not to stand by and do nothing," he says.
Montori and colleagues wrote that it is "at present, impossible to justify" the use of Avandia and Actos -- the two approved drugs in the class also commonly known as glitazones -- for use in at-risk patients.
"If clinicians offer patients glitazones to prevent diabetes, they are offering certain inconvenience, cost, and risk for largely speculative benefit," they write. "Lifestyle changes are clearly at least as effective as glitazones and can be implemented considerably more cheaply."
Calls from WebMD to Avandia manufacturer GlaxoSmithKline were not returned in time for publication.