Doctors aren't so sure that the Avandia-exonerating safety study is as conclusive as presented at the American Diabetes Association meeting. Some physicians are calling the study "flawed." In an editorial in the Lancet--where the research was published--two doctors wrote that the study's limitations prevent any "definitive conclusions" about Avandia's effects on cardiac safety.
Avandia has been haunted by safety concerns for two years, ever since an analysis found that patients using the diabetes med were more likely to suffer a heart attack than people taking other diabetes remedies were. Yesterday we reported that a GlaxoSmithKline-funded study--known as Record--had found that Avandia does not boost overall cardiovascular risk, though it does increase the risk of heart failure. "Record provides important and reassuring information about Avandia for physicians fighting diabetes," said Dr. Ellen Strahlman, GSK's chief medical officer, said in a statement on the study's release. "Clinical outcomes trials like this offer the highest standard of evidence when considering the benefits and risks of medicines."
But these doctors beg to differ. They told the Wall Street Journal that the overall rate of cardiovascular problems among patients in the trial was abnormally low. A significant number of Avandia patients took statins--10 percent more than the non-Avandia users, Forbes reports--and those cholesterol-fighters are known to cut heart attack risk. Plus, a relatively high level of patients dropped out of the trial entirely, which could have compromised the results, they said. (Glaxo said about 45 percent of participants dropped out at some point, but that dropout rate didn't affect the primary aim of the study.)
Meanwhile, another physician told the WSJ that the Record trial may have been too small to be sure Avandia is clear of increased heart attack risk. And Forbes is questioning the fact that Glaxo didn't reveal up front that so many patients had dropped out of the Record study. Steve Nissen, the cardiologist who launched the Avandia controversy with his meta-analysis, went so far as to call the trial "worthless" because of the dropouts and the statin-drug use.
Moreover, James Stein of the University of Wisconsin-Madison told Forbes that Record patients and doctors knew which drugs they were on, weakening the result. Plus, in a subset of Avandia patients who had established heart disease, the risk of heart attack increased by nearly 26 percent, he said. So it appears the debate over Avandia is far from over.