Avandia® (rosiglitazone)--Are Marginal Benefits Worth the Risk?
December 22, 2008 -- The most recent study on Avandia®, released November 24, 2008, found death rates were 15 percent higher among patients treated with diabetes drug rosiglitazone (Avandia®), compared to those taking pioglitazone (Actos®), and the incidence of congestive heart failure was 13 percent higher. This new study echoes earlier findings of increased congestive heart failure risk associated with Avandia®.
"The big attraction of these drugs is that they are insulin-sensitizing drugs and forestall the time when someone would have to go on to insulin," said Dr. Sidney Wolfe, director of Public Citizen's Health Research Group. "But with a 15 percent excess mortality over even pioglitazone, which itself is dangerous, that doesn't seem like a very good tradeoff."
Further findings from the new study indicated that patients taking Avandia® did not suffer an increased incidence of heart attacks compared to other treatments. Dr. Wolfgang C. Winkelmayer, assistant professor of medicine at the Harvard Medical School and first author of the study, suggested that the higher death rates among patients taking Avandia® might be due to cardiovascular disease in patients that had not been previously diagnosed.
"In much older adults, it is possible if they do have a stroke or myocardial infarction (heart attack), they might actually die immediately and never make it to the hospital for a diagnosis, so the excess cardiac events might show up as deaths," Dr. Winkelmayer said.
Avandia® has not been removed from the market by the FDA and is still available by prescription. It is estimated that roughly one million Americans continue to take the drug as part of their diabetes medication regime despite an increase in warnings and demonstrated safety concerns.
Avandia® Safety Center of Medical Controversy
Avandia® has been the center of a safety controversy since 2007, when authors of a study published in the New England Journal of Medicine were tied to a political move to rush information to the public before the FDA could issue a safety statement. The controversial Nissen and Wolski report concluded that there was a significant increase in the risk of myocardial infarction (heart attack) and an increase in the risk of death from cardiovascular causes that had borderline significance. The report also acknowledged limitations by lacking access to original source data for the 42 studies included in the analysis.
Reviews of the Nissen report concluded several limitations of the Nissen analysis: citing a lack of comprehensive data, varying inclusion and exclusion criteria and drug dosing regimens. A response in the Annals of Internal Medicine even suggested that the decision to pool all studies, despite design and population heterogeneity, probably led to artificial inflation and affected the accuracy of the risk estimate.
A follow up report, published in the Journal of the American Medical Association (JAMA), utilized a stricter dataset utilizing only long-term trials of Avandia®. The results were similar--an approximate doubling in risk of heart failure and a 42 percent increase in the risk of myocardial infarction (heart attack) without any effect on cardiovascular mortality.
Other Avandia® News:
August 3, 2007 FDA Recommends Warning Label for Avandia July 20, 2007 Increase in Side Effect Reports from Diabetics/ Avandia Users June 22, 2007 FDA Slow to Issue Avandia Safety Warnings June 1, 2007 New England Medical Journal: Avandia Shows Increase in Heart Attacks