Low-Dose Aspirin Reduces Stroke Risk for Women

But the drug only cuts heart attack risk in older women, study finds

MONDAY, March 7, 2005 (HealthDay News) -- Low-dose aspirin therapy considerably reduces the risk of stroke for women, a long-awaited study shows.

But it only helps to lower rates of heart attack and other cardiac problems in women 65 and older.

The report comes from the decade-long Women's Health Study, the first trial whose scale is similar in size to preventive studies done in men. The findings were to be presented Monday at the American College of Cardiology scientific sessions in Orlando, Fla.

Results of the study, which included nearly 40,000 middle-aged and older women, provide "the evidence base needed for women to make rational decisions about the use of aspirin in preventing cardiovascular disease," said Julie E. Buring, a professor of medicine at Brigham and Women's Hospital and Harvard Medical School, who presented the report.

The results differed from those found in similar large-scale studies of men, in which aspirin has been found to lower the risk of a first-time heart attack but have little effect on the risk of stroke. In the women's study, the pattern of benefit was clearly different.

The reduction in risk of stroke -- 17 percent for all types of stroke, and 24 percent for ischemic stroke, which is caused by blockage of a brain artery -- was highly significant because "we have more strokes than heart attacks in women," Buring said.

The benefit of low-dose aspirin in preventing cardiovascular problems was concentrated in the 10 percent of participants in the study who were 65 and over. They experienced one-third of all the cardiovascular events reported in the study. Among these women, low-dose aspirin reduced the risk by 26 percent, compared to women taking a placebo.

The study also produced an important negative result, she said. Because some previous studies have shown a benefit from taking vitamin E, some women in the trial were given daily doses of 600 International Units of the vitamin.

"The conclusion was that there is no benefit for cardiovascular disease in taking vitamin E supplementation," Buring said. "It is better just to eat heart-healthy foods."

Women of all ages and their physicians will have to balance the benefits and risks of low-dose aspirin, she said. There were 127 bleeding episodes requiring transfusion among women taking aspirin, compared to 91 such events among those taking a placebo, she said. The difference in risk -- 0.6 percent for aspirin, 0.5 percent for placebo -- is statistically significant and must be considered when making a decision, Buring said.

The decision about taking low-dose aspirin must be made for each individual woman, she said. "It should be made on a personal basis, a woman consulting with her physician and balancing benefit and risk."

Similar sentiments were echoed by Dr. Elizabeth G. Nabel, director of the National Heart, Lung, and Blood Institute, which supported the study.

Consult your doctor, Nabel said in a prepared statement. "Above all," she added, "women, like men, should adopt the well-proven approaches that reduce the risk of heart disease -- eating for heart health, getting regular physical activity, maintaining a healthy weight, not smoking, and controlling high cholesterol, high blood pressure, and diabetes."

The full study will be published in the March 31 issue of the New England Journal of Medicine.

Another report scheduled for presentation at the cardiology meeting Monday described the success of a device that uses electrical impulses to synchronize the beating of the heart to increase survival of patients with severe heart failure.

The trial included 813 patients treated at 82 medical centers in Europe. Half were given standard medical therapy, while the others got the same therapy but also had implanted devices that delivered electrical impulses to the pumping chambers of the heart.

Over a 30-month period, the death rate was one third lower in the patients who got the synchronizing devices, the report said -- 20 percent in the synchronized group compared to 30 percent in the group getting standard treatment. Patients who got the devices had fewer complications and better overall health than those who didn't.

Use of the devices "should routinely be considered" for people with severe heart failure, the researchers said in the study, which will be published in the April 14 issue of the New England Journal of Medicine.

More information

The American Heart Association has more on aspirin therapy.

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