At first glance, the raw data from the studies would seem to indicate a difference in male vs. female response to Plavix. The drug reduced cardiovascular events by 16 percent in men and 7 percent in women. The chief benefit for women was reduction of heart attack risk; for men it was reduction of strokes and cardiovascular deaths.
"But you have to look at the absolute benefit," Berger said. "What is the absolute difference? If we treat 1,000 men for eight months, we prevent 12 cardiovascular events. If we treat 1,000 women, we prevent eight cardiovascular events. We are not saying there are no differences between men and women. We are saying there are no significant differences."
The significance of the differences was of major concern to the cardiologists who did the study, Berger said. "We really discussed this at length, how to convey this data," he said.
The major risk of Plavix and other antiplatelet drugs is excess bleeding. The raw data showed that adding Plavix to aspirin increased the risk of major bleeding in women by 43 percent and in men by 21 percent.
"If you treat 1,000 men, you will have approximately five major bleeding events, and if you treat 1,000 women, you will have two major bleeding events," Berger said.
In an accompanying editorial, Dr. David P. Faxon, vice chairman of medicine at Brigham and Women's Hospital in Boston, wrote that "the cumulative evidence continues to show that women with coronary artery disease differ from men in many important ways, including the response to antiplatelet therapy."
"The good news is that clopidogrel is an exception," he wrote.
Adequate numbers of women need to be included in future cardiovascular studies "because outcomes cannot be predicted by mostly male-dominated trials," the editorial continued.
The new study doesn't settle the issue entirely, Faxon said. "A meta-analysis, putting together data from many
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