Study flags Avandia risks

A new Canadian study provides the strongest evidence to date of the dangers of the popular diabetes drug Avandia, particularly when used by seniors.

The research, published in today’s edition of The Journal of the American Medical Association, is the latest in a series of studies calling the safety of the drug into question.

Older diabetics taking the drug have a risk of congestive heart failure 60 per cent higher than those taking other diabetes drugs, the study found. Those on the drug also show a 40-per-cent jump in the risk of heart attack and a 29-per-cent increase in the risk of death.

“It looks like the risks of this drug outweigh its benefits in older people with diabetes,” Lorraine Lipscombe, a researcher at the Institute for Clinical Evaluative Sciences and lead author of the study, said in an interview.

“We hope that the experts – particularly the regulators – will take our data seriously and act appropriately,” Dr. Lipscombe said.

Health Canada has already stated that rosiglitazone (Avandia) should not be used as a stand-alone therapy, except by patients who cannot tolerate other diabetes drugs. The U.S. Food and Drug Administration, for its part, has slapped a black box on Avandia’s label, the most severe warning the agency can issue.

However, the FDA released a statement yesterday in response to the study saying it has no plans to change its approach, and the drug will remain on the market.

David Alter, a senior ICES scientist and co-author of the study, urged patients to act cautiously on the new data.

“We don’t want people to panic,” he said, in encouraging patients to discuss the issue with their physicians.

The drug’s maker, GlaxoSmithKline, rejected the conclusions of the research.

It issued a written statement saying the study “has significant limitations and generates misleading conclusions regarding acute myocardial infarction and death.”

In particular, it said the patients in the study taking Avandia were older and sicker, so their higher rates of heart disease and death were not surprising.

But Avandia is prescribed precisely to those people who have not done well on other treatments, said Dr. Lipscombe, who is also an endocrinologist at Women’s College Hospital in Toronto. She also noted that while earlier research suggested that people with a history of cardiovascular disease – and heart failure in particular – should avoid Avandia, the new data show that even those with no history of heart problems are at increased risk.

Doctors issued 1.2 million prescriptions for Avandia in Canada during the past year, with sales exceeding $151-million, according to IMS Health Canada, a private company that tracks prescription drug sales. Worldwide, Avandia sales top $3-billion (U.S.) annually.

There are a number of class-action lawsuits that have been launched in Canada and the United States alleging that GlaxoSmithKline did not provide adequate warning of the potential dangers of the drug.

Kyle Goomansingh of Winnipeg is one such claimant. His father Vic died in May, at age 69. One of the drugs he was taking was Avandia.

“He basically woke up that morning singing. He had lunch, and at 1:30 in the afternoon he collapsed,” Mr. Goomansingh said. The elder Mr. Goomansingh, a retired school teacher, was thin and fit but had suffered from diabetes for more than a decade. Still, “it seemed odd for someone in his 60s to just die suddenly like that,” his son said.

After reading media reports about the increased risk of heart attacks and heart failure among patients taking Avandia, the younger Mr. Goomansingh contacted a lawyer. More than anything, he said, he is seeking answers.

“I know that no drug is perfect but this type of occurrence should be minimized.”

The new study involved 159,026 Ontario residents over the age of 65 who suffered from diabetes and were taking drugs to treat the condition.

There are a wide array of drugs that diabetics take to control blood-sugar levels, including metformin, sulfonylureas and thiazolidinediones. The latter, TZDs including rosiglitazone and pioglitazone (Actos), are drugs that promised better control of blood sugars and fewer heart problems.

But these drugs actually promote edema (fluid retention) and weight gain, posing a particular risk to patients with heart failure.

The new study, however, found the increased risks were limited almost exclusively to Avandia, though the authors noted that there were very few patients taking Actos.

Amir Hanna, staff endocrinologist at St. Michael’s Hospital in Toronto, said TZDs still have an important role in treating diabetes, but physicians have to be careful to prescribe them to the right patients, in particular avoiding those with underlying heart or kidney disease. “I don’t think this is the last nail in the coffin of Avandia or Actos,” he said.

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