An aspirin a day doesn’t lessen the risk of dying from a heart attack or stroke in people who have never previously experienced either, researchers in Japan report. The commonly used drug also fails to protect against nonfatal strokes and increases the risk of intracranial bleeding, they find.
But the study presents a muddled picture. People taking low doses of aspirin had fewer nonfatal heart attacks and fewer ministrokes than did people who were not taking the drug.
Even so, the 6.5-year study was stopped after five years when it became clear that aspirin was failing to lower death rates. The results appear November 17 in JAMA and were presented in Chicago at a meeting of the American Heart Association.
Physician Yasuo Ikeda of Waseda University in Tokyo and colleagues enrolled 14,464 people age 60 to 85 with no history of heart disease or stroke. All enrollees had at least one cardiovascular risk factor, such as high blood pressure, diabetes or high cholesterol. Most had at least two.
Half of the participants were randomly assigned to take a daily dose of aspirin slightly higher than a baby aspirin; the others were not. After five years, 56 people in each group had died of a heart- or stroke-related cause. Those taking aspirin had 20 nonfatal heart attacks while 38 did in the group not getting aspirin. But the aspirin group had 23 bleeds within the skull compared with 10 among the others. There was no substantial difference in nonfatal ischemic strokes, the kind caused by blood clots in the brain.
The findings bolster earlier studies showing inconsistent benefits from aspirin in people who have never had a heart attack or stroke, says cardiologist J. Michael Gaziano of the VA Boston Healthcare System and Brigham and Women’s Hospital. Collectively, these findings underscore the need for people to consult a doctor before taking aspirin to assess the trade-offs, he says.
“The math says that that if you are above a certain level of risk for heart attack and ischemic stroke, it makes sense to use aspirin,” he says, because the clot busting would outweigh negatives such as risk of bleeding in the gastrointestinal tract or brain. What’s more, this calculation must take into account another trade-off: Aspirin seems to protect against colorectal cancer, Gaziano says.
The Japanese team plans to assess cancer mortality by running another analysis of the aspirin trial data. Meanwhile, several other aspirin studies are under way in the United States, Europe and Australia.