Aspirin can significantly reduce death rates for postmenopausal women with heart disease, according to a new analysis by Duke University Medical Center cardiologists. Furthermore, the researchers found the same beneficial effect for low-dose aspirin (81 mg a day) as for higher dose aspirin (325 mg).
These findings are important because they provide a scientific basis for recommending that more postmenopausal women should take aspirin, the researchers said. In their analysis of 8,928 women, the researchers found that fewer than half were taking any aspirin at all.
"The fact that more women are not taking aspirin is very discouraging," said Duke cardiology fellow Jeffrey Berger, M.D., who presented the results of his analysis on Nov. 14, 2005, at the annual scientific sessions of the American Heart Association in Dallas. "Aspirin is a drug that has been used for many years - it is effective, inexpensive and widely available.
"We know that aspirin can save the lives of postmenopausal women with cardiovascular disease, so the percentage of those women taking aspirin should be in the high 90 percent," Berger continued. "The only reason for these women not to be taking aspirin is if they have an allergy or suffer severe side effects."
For his study, Berger analyzed the data collected by the Women's Health Initiative Observational Study, a National Institutes of Health-funded project that has been following 93,676 postmenopausal women between the ages of 50 to 79 since 1994. The women participating in the study were not required to take any medications, nor were they asked to change their health habits.
Of that large cohort of women, Berger identified 8,928 women who had cardiovascular disease, including women who had suffered a heart attack, stroke, transient ischemic attack (TIA or mini-stroke), or who had cardiac chest pain or a prior procedure to open clogged coronary arteries. During the 6.5 years of the study, 8.7 percent of the women died.
Berger found that only 46 percent of these women were taking aspirin on a regular basis. Compared to the women who did not take aspirin, those who did showed a 17 percent reduction in all-cause mortality. The women taking aspirin also demonstrated a 25 percent reduction in deaths associated with cardiovascular disease.
"When we looked at outcomes such as all-cause mortality or any other cardiovascular event, we found no significant difference between the two doses," Berger said. "For that reason, we not only encourage all postmenopausal women to talk with their doctors about taking aspirin, but if the doctor recommends aspirin, it should be taken at the lowest possible effective dose."
In terms of aspirin dosage, 30 percent of women took 81 mg daily, while 70 percent took 325 mg daily. An 81 mg dose is the equivalent of a baby aspirin. Berger also found that both dosages were associated with non-significant reduction in the number of cardiovascular events.
Berger pointed out that since this was an observational study and not a randomized clinical trial, it is not possible to state that aspirin was the actual cause of the outcome improvements. However, he did add that the population is a "real-world" group of patients, since the women who participated came from across the country, from rural and urban settings, and from all socioeconomic groups.
While the beneficial effect of aspirin for men is well-documented, the case is different for women.
"All the major clinical trials studying the potential of aspirin either excluded women altogether or were predominantly men," Berger explained. "Also, elderly women have been even less studied, and these are the women who are most likely to benefit from aspirin as a preventative measure."
Other members of the team included David Brown, SUNY-Stony Brook School of Medicine; Gregory Burke, Wake Forest University, Winston-Salem, N.C., Albert Oberman, University of Alabama-Birmingham; John Kostis, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, N.J.; Robert Langer, University of California-San Diego; Nathan Wong, University of California-Irvine; and Sylvia Wassertheil-Smoller, Albert Einstein College of Medicine, NY.