Results Of Yale Study Confirm Aspirin Helpful In Preventing A First Heart Attack

The studies included more than 51,000 people and 2,284 "vascular events": vascular disease-related death, cardiac or cerebral; nonfatal heart attack, or nonfatal stroke. The overview article was published in the Archives of Internal Medicine.

"The results reconfirm that aspirin is beneficial in preventing a first myocardial infarction," said Patricia Hebert, associate research scientist in the Department of Medicine, Cardiology, at Yale School of Medicine. "We really did not have enough events to assess the effects of aspirin on overall stroke, ischemic stroke, or cardiovascular death. There was an increase in the risk of hemorrhagic stroke from taking aspirin, which also has been detected in secondary prevention trials."

Individuals that took aspirin had a 32 percent reduction in nonfatal heart attacks. Aspirin did not appear to reduce the number of vascular disease-related deaths, nor lead to any significant decrease in the number of overall or ischemic strokes. There was, however, a slight increase in the risk of hemorrhagic stroke associated with aspirin use.

The overview included four primary prevention trials of aspirin and cardiovascular disease: The Physicians Health Study, The British Doctors’ Trial, The Thrombosis Prevention Trial, and The Hypertension Optimal Treatment Study.

"In primary prevention, there is conclusive benefit of aspirin in reducing risk of a first myocardial infarction and any important vascular event," Hebert said. "Whether there are any beneficial effects on risks of vascular deaths, overall stroke, or ischemic stroke remains uncertain due to inadequate numbers of events in the primary prevention trials completed to date. While based on small numbers, the available evidence suggests an increased risk of hemorrhagic stroke that needs to be further investigated."

Hebert said more randomized trial data, especially in women, is needed to help formulate a rational public health policy for individuals at usual risk of suffering a heart attack or stroke. In the meantime, she said, these data provide evidence for a significant benefit of aspirin therapy in the primary prevention of myocardial infarction.

Co-author of the study was Charles Hennekens, M.D., visiting professor of Medicine & Epidemiology and Public Health at the University of Miami School of Medicine.