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Daily low-dose aspirin is not a panacea for the elderly

In fact, taking aspirin regularly may harm healthy older people

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9:30am, September 19, 2018
person holding aspirin tablets

PUT IT AWAY  Healthy elderly adults should skip a daily dose of aspirin because the health benefits are minimal, and the risk of internal bleeding is high, three related papers from a large clinical trial suggest.

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A daily dose of aspirin? Not a good idea if you’re a healthy elderly adult.

A trio of papers based on a large-scale clinical trial finds that the drug doesn’t help to stave off heart attacks, strokes, dementia or physical disability. In fact, those in their golden years who took a low dose of aspirin daily were more likely to suffer serious internal bleeding than those who took a placebo. The researchers even observed more deaths among those on aspirin, although that result wasn’t statistically significant.

The clinical trial, called ASPREE or Aspirin in Reducing Events in the Elderly, included more than 19,000 adults. About half of those adults were randomly assigned to take 100 milligrams of aspirin per day and the other half a placebo pill for around five years.

The papers, published online in the New England Journal of Medicine on September 16, “once again remind us that aspirin is not a benign drug,” says cardiologist Jeffrey Berger of New York University School of Medicine who was not part of the research.

“There’s a lot of misunderstanding of the original data in support of aspirin,” he says. The notion that everyone in older age should take aspirin to prevent a first heart attack or stroke, Berger says, “is not born out from the evidence to date.” Yet a 2015 study found that nearly half of 2,039 U.S. adults ages 45 to 75 who didn’t report a history of cardiovascular disease were regularly taking aspirin.

Here are a few of the key findings from the new studies, as well as some common points of confusion over medical guidance for taking aspirin.

Does aspirin protect against heart attacks?

Yes, if you already have had a heart attack or stroke or have coronary artery disease. “If you’ve had a heart attack, it’s not debatable: Aspirin saves lives,” Berger says. Clinical trials have shown that low-dose aspirin significantly reduces subsequent heart attacks and strokes in those patients, equating to about 10 to 20 fewer of these events per 1,000 people per year. That benefit outweighs the increases seen in occurrences of internal bleeding.

What’s unsettled is whether aspirin can help prevent a first heart attack or stroke in people without cardiovascular disease, and the new work casts additional doubt. Official recommendations are mixed, too. The latest U.S. Preventive Services Task Force guidelines, from 2016, recommend that people aged 50 to 59 who have at least a 10 percent risk of developing cardiovascular disease take up to 100 milligrams of aspirin daily. The organization also finds some evidence that the dose may be slightly beneficial for those 60 to 69 with that same cardiovascular disease risk. But the U.S. Food and Drug Administration does not support using aspirin for preventing a first heart attack or stroke, arguing the evidence lacking.

In the new research, Anne Murray, a geriatrician and medical director of the Berman Center for Outcomes and Clinical Research at Hennepin Healthcare in Minneapolis, and her colleagues wanted to study whether aspirin was helpful for preventing cardiovascular disease for even older adults. The researchers’ trial included Australians and some Americans 70 and older, with black and Hispanic American participants aged 65 and older, although most participants were white.

The rates of cardiovascular disease, including heart attacks and stroke, were about the same between the aspirin and placebo groups: 10.7 events per 1,000 people per year on aspirin and 11.3 events per 1,000 people on the placebo. But those on aspirin were significantly more likely to develop a major hemorrhage, or bleeding, in the stomach, intestines or brain, with 8.6 events per 1,000 people compared with 6.2 events per 1,000 people on the placebo.

Why did the researchers also investigate dementia and disability?

“Those are the two things that play the largest role in whether people are able to remain independent” in their later years, Murray says. She and her colleagues thought that the blood-thinning and anti-inflammatory properties of aspirin might decrease the risk of dementia and physical disability by ameliorating small vessel disease, or abnormalities in the brain’s small blood vessels that have been linked to impairments in thinking and movement.

But that hypothesis didn’t pan out. The combined rates of dementia, physical disability and death were nearly the same between the aspirin and placebo groups: 21.5 events versus 21.2 events per 1,000 people per year, respectively.

“There really are no measurable benefits of taking low dose aspirin” for healthy elderly adults, Murray says. “Certainly the benefits don’t outweigh the risk of bleeding.”

Doesn’t aspirin reduce the risk of some cancers?

Yes, for colorectal cancer. Aspirin taken long-term, especially for 10 years, reduces the risk of this cancer, according to numerous studies. The U.S. Preventive Services Task Force recommends aspirin for people aged 50 to 59 to prevent colorectal cancer, finding the evidence is strongest for these adults.

Surprisingly, in the new work, “we did find that cancer made up the highest proportion of people who died,” among those in the aspirin group, Murray says. “That was unexpected, and we’re not clear why.” The trial didn’t find that aspirin increased or reduced cancer risk in healthy elderly adults.

The researchers want to study aspirin use in these elderly adults for five more years to see if longer-term use offers any protection against cancer in this age group, and if so, whether it outweighs the higher risk of internal bleeding.

Citations

J. McNeil et al. Effect of aspirin on disability-free survival in the healthy elderly. NEJM. Published online September 16, 2018. doi:10.1056/NEJMoa1800722.

J. McNeil et al. Effect of aspirin on all-cause mortality in the healthy elderly. NEJM. Published online September 16, 2018. doi:10.1056/NEJMoa1803955.

J. McNeil et al. Effect of aspirin on cardiovascular events and bleeding in the healthy elderly. NEJM. Published online September 16, 2018. doi:10.1056/NEJMoa1805819.

Further Reading

N. Seppa. Aspirin, other painkillers may not reduce colorectal cancer risk for everybody. Science News. Vol. 187, April 18, 2015, p. 16.

N. Seppa. Aspirin’s heart benefits not a slam dunk. Science News Online, November 18, 2014.

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