Elderly Warned About Aspirin Use : Medicine: Findings in a USC study seem sure to stir controversy. They conflict sharply with earlier claims that the drug can stave off heart attacks.
Daily use of aspirin is statistically linked to an increased risk of cardiovascular diseases in elderly individuals who have never had heart disease, angina or strokes, according to a study by researchers at the USC Medical School that is being published today in the British Medical Journal.
The findings are likely to trigger controversy and confusion because they appear to conflict sharply with the widely publicized U.S. Physicians’ Health Study. The final results of that study, published in the New England Journal of Medicine in July, found that an aspirin every other day can cut the risk of first heart attacks in half for men over 50.
Dr. Charles H. Hennekens, the Harvard Medical School cardiologist who directed the earlier study, said the conclusions of the USC researchers were “far off-base. . . . The totality of evidence is that aspirin reduces the risk of a heart attack.”
Evaluation of the role of aspirin in preventing heart diseases is further clouded by significant differences between the design of the two studies.
The Physicians’ Health Study involved 22,071 male physicians age 40 to 84 years who were followed for about five years. It was a randomized experiment, where two similar groups of subjects were assigned to take aspirin or a placebo pill every other day. To avoid bias, neither the patients nor the researchers knew which subjects were taking aspirin or placebo pills.
The newly released USC study, on the other hand, was a postal questionnaire survey of elderly men and women, whose median age was 73. The health status of self-reported aspirin users and non-users was followed for 6 1/2 years. Aspirin use ranged from several times a day to weekly or monthly to not at all.
In general, randomized control trials are considered a more reliable way of gathering scientific data than observational studies, where there is no way to determine who gets the drug that is being studied, how often it is taken and why it is being used.
As part of an on-going study of about 14,000 residents of Leisure World, a retirement community in Laguna Hills, the USC researchers found that 1,579 previously healthy daily aspirin users had about a 40% increased risk of developing all cardiovascular diseases when compared to 7,756 residents who did not take aspirin. Those who took aspirin every other day or less frequently were not at increased risk.
The USC researchers did find a reduced incidence of first heart attacks--but not of strokes and other heart diseases--in men who were daily aspirin users compared to those who were not. But the reduced incidence of first heart attacks in men was not statistically significant, and no similar trend was found for elderly women.
Most of those surveyed said they were taking aspirin for arthritis; about a quarter said they were using the drug to try to prevent heart disease.
“I don’t think our results are that different (from the other study),” said Annlia Paganini-Hill, principal author of the USC study. “It is just that we interpreted them differently.”
The USC researchers emphasized the association between aspirin and the overall risks of developing cardiovascular diseases, which include strokes, heart attacks, the heart-related chest pain known as angina and abnormal heart rhythms.
The Physicians’ Health Study emphasized the reduction in the risk of both fatal and non-fatal heart attacks. The study found no statistical link between aspirin use and reduction in deaths from all cardiovascular causes.
Heart attacks occur when the blood supply to a section of heart muscle drops below a critical level and the tissue dies. Aspirin is thought to prevent heart attacks by interfering with the ability of blood clots to form in the arteries that supply blood to the heart.
Paganini-Hill said that based on “the knowledge we have available at this time,” it is “not advisable” for healthy individuals to take aspirin on a daily basis to try to forestall heart disease.
In a telephone interview from Boston, Hennekens of Harvard reiterated his view that patients and their physicians should reach “individual judgments” about the use of aspirin. “Aspirin is not for all (but only for) those whose risks of heart attacks are sufficiently high to warrant the side effects,” he said. These side effects include stomach upset, gastrointestinal bleeding and a potential increased risk of strokes.
Both Paganini-Hill and Hennekens cautioned that their comments were directed at individuals with no history of heart disease. Both cited substantial medical evidence that aspirin and other so-called “anti-platelet” agents could prevent heart attacks, strokes and heart-related deaths in individuals with previous heart attacks, strokes or angina.
In October, an advisory committee to the U.S. Food and Drug Administration reviewed the Physicians’ Health Study. While acknowledging a significant decrease in the incidence of first heart attacks, the committee “discerned no effect” on total cardiovascular deaths.
The committee concluded that aspirin might be used to prevent first heart attacks in some high-risk men but that it “should not be used routinely” as a preventive measure in low-risk men or in women.
