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Debate Renewed: Diabetes drug ups heart risk

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11:06am, September 12, 2007
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The popular diabetes drug rosiglitazone, marketed as Avandia, more than doubles the long-term risk of heart failure and increases the long-term risk of heart attack by 42 percent, according to a new analysis.

Rosiglitazone initially came under scrutiny earlier this year when an analysis of short-term trials found a 43 percent increase in risk of heart attack among people taking the drug (SN: 6/23/07, p. 397). The Food and Drug Administration called an emergency advisory committee meeting, and in July that group agreed that the drug increases the risk of heart attack. However, the panel recommended that the FDA keep rosiglitazone on the market. The agency is now reviewing data and weighing options on the drug.

To clarify the long-term heart risks of rosiglitazone, Sonal Singh of Wake Forest University School of Medicine in Winston-Salem, N.C., zeroed in on studies lasting a year or longer that specifically tracked the cardiovascular health of participants. Of 140 past human trials of the drug, only 4 met those criteria.

Singh and his colleagues pooled the data from those four studies, which included 14,291 patients. Of 6,421 patients who took rosiglitazone for at least a year, 94 suffered heart attacks and 102 experienced heart failure, a progressive condition in which the heart struggles to pump blood. In 7,870 patients who took either a placebo or another diabetes medicine, 83 suffered heart attacks and 62 experienced heart failure.

Those figures equate to a 42 percent increase in risk of heart attack and a 109 percent increase in risk of heart failure among patients taking rosiglitazone for at least a year. In absolute terms, 1 in 30 patients taking the drug will develop heart failure and 1 in 220 will have a heart attack because of the drug, according to the researchers.

Philadelphia-based GlaxoSmithKline, the maker of rosiglitazone, estimates that a million people in the United States take the drug.

"The public health impact of potential harm ... is substantial," Singh and his colleagues write in the Sept. 12 Journal of the American Medical Association. Singh, an internist, says that he no longer prescribes rosiglitazone. He chastised the FDA for keeping it on the market. "They want absolute proof of harm before they take action," he says. "Who's going to provide that proof?"

Sen. Charles Grassley (R–Iowa), who advocates tightened FDA oversight, points to the new report as "a case study in what's wrong with the [FDA's] drug-safety system .... FDA's relationship with drugmakers is too cozy."

GlaxoSmithKline issued a statement saying that the new report "is yet another iteration of previously analyzed data, and offers no new information on the safety of Avandia.... We believe it is inappropriate for the author to advise doctors to disregard the FDA's advice, which is to keep patients who are effectively controlling their diabetes on Avandia."

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