Increased Risk of Brain Bleed in Older Adults Linked to Daily Low-Dose Aspirin Use

Taking daily, low-dose aspirin may increase older adults' risk of brain bleeds while doing very little to lower the risk of ischemic stroke, a new study finds.

While it was at one point fairly common for older adults to be advised to take low-dose aspirin for the sake of stroke prevention, research—and the paralleling medical advice—is shifting.

The new research is the latest evidence to show that routine use of low-dose aspirin is not suited for older adults with no history of heart conditions or history of strokes. Findings did suggest that older people who are prone to falls, which can cause brain bleeds, should be cautious of taking aspirin.

“Amongst older people, low-dose aspirin appears to lead to an increased risk of intracranial hemorrhage of various types,” Professor John McNeil, an author of the paper and Professor of Epidemiology & Preventive Medicine at the School of Public Health & Preventive Medicine at Monash University told Health.

'It emphasizes the need to avoid aspirin as a primary preventive intervention in older people,” McNeil said.

The study used data from Aspirin in Reducing Events in the Elderly (ASPREE), the largest randomized controlled trial of low-dose aspirin, to organize their participant pool.

The 19,114 participants were from Australia and the United States, reported their race or ethnicity as Black or Hispanic, and were over the age of 70. They did not have any symptomatic cardiovascular disease, and anyone with a history of stroke or heart attack was not included in the study.

The research team randomly assigned 9,525 people to take 100 milligram daily doses of aspirin and 9,589 people to take placebo pills. The study then followed participants for a median of 4.7 years in hopes of better understanding the link between daily, low-dose aspirin use and brain bleeds.

“In the elderly, the risk of bleeding is substantially more common than in younger people and the trade-off between a possible reduction of ischemic strokes and an increase in intracerebral bleeding has not been reported,' McNeil said.

The study found a significant increase–38%—in intracranial bleeding resulting from a combination of hemorrhagic stroke and other causes of intracerebral hemorrhage among individuals who took aspirin.

Researchers found that 312 participants had their first ischemic stroke during the study. Of these, 24 people died due to the stroke. In addition, 187 people had bleeding inside the skull, which included people who had a hemorrhagic stroke.

Aspirin also appeared to reduce the occurrence of ischemic stroke, though not statistically significant, according to researchers.

McNeil noted that these findings provided another reason to avoid the use of aspirin in older people who do not need to be taking it.

“They support the conclusions of the guidelines released last year by the US Preventive Health Task Force (USPSTF) advising against initiating aspirin for primary prevention in people over 70 years,” he said.

The new data also supports the recent recommendation of the USPSTF, that low-dose aspirin should not be prescribed for preventing a first heart attack or stroke in healthy older adults.

In addition to its anti-inflammatory effects, which have been well known since ancient times, aspirin prevents blood clot formation by inhibiting the aggregation of platelets in the bloodstream, Jordan Amadio, MD, an attending neurosurgeon at the Department of Neurosurgery, Dell Medical School at the University of Texas at Austin, told Health.

While this may help reduce the risk of clots, the side effect of this is an increased risk of bleeding that does not stop easily.

“Bleeding into the brain, which is like a bomb exploding into a neighborhood of dense high-priced real estate, can be catastrophic,” Amadio said. “Older adults are at higher risk for brain bleeding for a variety of reasons, including poorly regulated blood pressure, fragile blood vessels prone to rupture, or head trauma due to falls.”

Low-dose aspirin, or baby aspirin, is commonly recommended to adults for preventing heart attacks and strokes.

“In popular culture, we sometimes think of ‘taking an aspirin’ as something benign and mild, but it is a powerful blood thinner with a variety of physiological effects,” Amadio told Health. “If aspirin were invented today, it is doubtful that you could buy it over the counter.'

He emphasized that aspirin should be used like any other medication—with a consideration of risks and benefits.

While some people who've had a heart attack take a daily baby aspirin as an effective heart attack prevention strategy, others with no history of cardiovascular disease or heart attack take it as well.

A 2019 study estimated that roughly 29 million Americans who have no history of heart attack or cardiovascular disease take aspirin daily, thinking it will prevent a first heart attack.

Nearly 7 million do it without the recommendation of a healthcare provider.

“For some people, the risk of daily aspirin use outweighs the potential benefits,” Karla Robinson, MD, Fellow at the American Academy of Family Physicians and Medical Editor at GoodRx told Health.

She encourages people to make this decision with a healthcare provider, taking into consideration your personal needs and history.

For patients with risk factors that may increase the risk of head trauma, like frequent falls, having a discussion with your healthcare provider about treatment options is the best option for you.

For patients that need to be on daily aspirin or still benefit from daily low-dose aspirin use, Robinson recommends checking with your healthcare provider to confirm the proper dosage and usage you’re taking, given your medical history.  

'This new study really highlights the importance of weighing the risk of having a brain bleed from aspirin treatment against your risk of ischemic stroke,' she said.