Aspirin, that familiar, inexpensive little white pill, has long been known to carry cardiovascular benefits in addition to its powers as an anti-inflammatory painkiller. "The real question is: 'Who is it for?' " says Jeffrey Berger, cardiologist at New York University Langone Medical Center. Identifying the exact groups of patients who will gain the most benefit from aspirin in relation to the risks the drug brings—a higher risk of bleeding, including in the brain, and possible gastrointestinal problems—is a bit more difficult than one might think. Research published today in the Journal of the American Medical Association suggests that older folks with no clinical cardiovascular disease who were flagged as being at increased risk—identified by a simple test that compares blood pressure in the ankle with that in the arm and can indicate peripheral artery disease—might not gain any protection from that daily aspirin, even though PAD is a form of cardiovascular disease.
The study, led by researchers at the University of Edinburgh in Scotland, tested whether people identified by the comparative blood pressure test known as the Ankle Brachial Index as being at higher risk for cardiovascular trouble would benefit from aspirin therapy. The study subjects were people ages 50 to 75 who were identified as being at greater risk by the ABI test. Compared with those who took a placebo, subjects who took a coated, 100-mg aspirin daily did not benefit in any significant way—measured by any difference in fatal or nonfatal coronary events and death from any cause. Subjects were followed for an average of eight years. Of 3,350 participants, 20 taking the placebo had a hemorrhage that required a hospital stay, compared with 34 taking the aspirin.
"I really question the use of aspirin" in people whose cardiovascular disease has not progressed to the point where they have symptoms, says Berger. He wrote an editorial in the issue of the Journal of the American Medical Association that published the study.
One thing is clear, says Sidney Smith, director of the Center for Cardiovascular Science and Medicine at the University of North Carolina–Chapel Hill: Aspirin works very well for "secondary prevention." That is, it helps prevent a second cardiovascular event—say, a heart attack or ischemic stroke—or is beneficial to someone who has established disease and has gotten a stent or had bypass surgery, for example. Yet "aspirin is not necessarily going to carry a benefit for everybody," he says. Smith is leading a group at the National Institutes of Health that is attempting to come up with more robust recommendations for the prevention of cardiovascular disease.
He notes, too, that the recommendation put out last year by the U.S. Preventive Services Task Force called attention to differences in risks and benefits by age and gender and by how great one's likelihood of a cardiovascular event is. The task force noted that while older folks are more likely to benefit from the protection aspirin offers, they are also more likely to have a bleed. And the benefits that adult men and women reap from daily aspirin differ. The USPSTF recommended that men ages 45 and 79 take a low-dose aspirin daily if they have risk factors for heart disease and heart attack. Women between ages 55 and 79 should do the same, the agency said, if they are at elevated risk of having an ischemic stroke. Importantly, the recommendation also said that physicians should consider the individual's risk of a bleed or gastrointestinal problems in weighing the decision to initiate aspirin therapy.
To the average adult who has not had a major cardiovascular event, popping a baby aspirin daily may seem like an easy, smart, cost-effective way to protect health; advertisements can certainly give people such an impression. But like much of medicine, it's just not that simple. An aspirin is no multivitamin. "We're not at the point where someone who is otherwise healthy should think there's one pill that they should take after their 50th birthday," says Smith.
Investigators continue to try to parse the benefits and risks of aspirin use, but more study is undoubtedly needed, Berger and Smith say. This slide show is a roundup of some recent findings about what aspirin may do to your health.