Aspirin provides less heart protection for women
By Megan Rauscher
New York (Reuters Health) - Gender may explain the considerable variation in the effectiveness of aspirin therapy in reducing the risk of heart attacks, researchers from Canada report. Their findings, published online in BMC Medicine, indicate that women may be much less responsive to aspirin than men.
Women with a low or average risk of having a heart attack "should probably not take aspirin as preventive therapy," Dr. Don D. Sin from the University of British Columbia, Vancouver, told Reuters Health.
In a comprehensive search of published studies, Sin and his colleagues identified 23 clinical trials, with a total of 113,494 participants, which examined the effectiveness of aspirin therapy in preventing heart attacks.
Overall, compared with placebo, aspirin therapy provided a modest reduction in the risk of non-fatal heart attacks (28 percent), but did not reduce the risk of fatal heart attacks, the team reports.
There was, however, considerable variation in the effectiveness of aspirin across the trials. According to the researchers, roughly 27 percent of the total variation in reports of non-fatal heart attacks could be explained by the proportion of men and women in the trial.
In general, studies that predominantly included men had the largest risk reduction in non-fatal heart attacks, at 38 percent, while trials that mostly included women failed to show a significant reduction in the risk of non-fatal heart attack.
"These data are consistent with the notion that aspirin is less efficacious in women (for the reduction of heart attacks) and raise the possibility that women are more susceptible to aspirin resistance," Sin and colleagues conclude.
SOURCE: BMC Medicine online October 18, 2007