• Posted July 27, 2023

Daily Baby Aspirin Raises Odds for Brain Bleeds, With No Lowering of Stroke Risk

For years, older adults took a baby aspirin a day to help ward off a first-time heart attack or stroke. Now yet another study is showing the risks are not worth it for most.

Specifically, researchers found the risk of brain bleeding while using low-dose aspirin outweighed any potential benefit against stroke for relatively healthy older adults -- that is, those with no history of heart disease or stroke.

In fact, among more than 19,000 older adults in the study, those who took daily low-dose aspirin for several years showed no reduction in their risk of an ischemic stroke (the kind caused by a blood clot).

They did, however, have a 38% higher risk of bleeding in the brain, compared to study patients given placebo pills for comparison.

Experts said the findings align with the latest recommendations on low-dose aspirin: Most people with no history of cardiovascular disease, including heart attack or stroke, should skip it.

"What's becoming clearer and clearer is that aspirin, for primary prevention, is not indicated for most people," said Dr. Anum Saeed, a cardiologist who was not involved in the study.

"Primary prevention" refers to prevention of first-time strokes or heart attacks.

The new findings do not apply to people who have been prescribed aspirin because they already have a history of those conditions, said Saeed, an assistant professor at the University of Pittsburgh Medical Center and a member of the American College of Cardiology (ACC) Prevention Council.

Dr. Mitchell Elkind, chief clinical science officer for the American Heart Association (AHA), said that while the study focused on older adults, the findings support what's recommended for younger people, too.

"They are consistent with current recommendations from professional societies, including the AHA, that most individuals of any age should not take aspirin for primary prevention," said Elkind, who was not part of the study.

For years, middle-aged and older adults were commonly advised to take a baby aspirin a day, to lower the risk of a blood clot forming and potentially triggering a heart attack or stroke. It was always known that aspirin carried a risk of internal bleeding -- in the stomach or, most troubling, the brain. But the benefits were believed to outweigh that risk for most people.

Within the past few years, however, medical groups like the ACC and AHA have changed their recommendations. The moves were based on new evidence showing that, for people with no preexisting heart disease, the balance of risks versus benefits has changed.

These days, people are smoking less and have their blood pressure and diabetes under better control, versus a few decades ago. Many are also taking statins, which cut the risk of heart attack and stroke. So the need for aspirin has waned.

That also means the risk of bleeding now looms larger.

The new findings -- published July 26 in JAMA Network Open -- come from an analysis of a previously reported clinical trial. It included more than 19,000 adults age 65 and older; about half were randomly assigned to take low-dose aspirin (100 milligrams per day), while the rest received a placebo.

Over the next four to five years, aspirin users were more likely to suffer brain bleeding: Just over 1% did, compared to 0.8% of placebo users. And there was no benefit to show for it. The rates of ischemic stroke were similar in both groups: 1.5% among aspirin users, 1.7% in the placebo group.

Elkind said there may be some exceptions to the "skip aspirin" advice: If a person between the ages of 40 and 70 is considered high risk for a heart attack or stroke, and at low risk of bleeding, aspirin might be considered.

People may be high risk due to a strong family history, for example, or a high score on coronary calcium testing, which indicates a buildup of plaques in the arteries.

"The key word here is routine," Elkind said. "Aspirin should not be considered routine or low-risk, and every patient should be considered individually based on their specific constellation of risk factors and bleeding tendency."

For people who are already on low-dose aspirin, Saeed said it's important not to stop on your own. Talk to your doctor about why it's been prescribed, and whether you should continue, she said.

Geoffrey Cloud, a professor of neuroscience at Monash University in Melbourne, Australia, and Dr. Jeff Williamson, of Wake Forest School of Medicine in Winston-Salem, N.C., led the study.

More information

The American Heart Association has more on aspirin.

SOURCES: Anum Saeed, MD, assistant professor, medicine, University of Pittsburgh Medical Center, and member, Prevention Council, American College of Cardiology, Washington, D.C.; Mitchell Elkind, MD, MS, chief clinical science officer, American Heart Association, Dallas, and professor, neurology and epidemiology, Columbia University Irving Medical Center, New York City; JAMA Network Open, July 26, 2023, online