By Melissa Cunningham
It was once deemed the “wonder drug” in the fight against heart attacks and strokes.
But an influential medical taskforce in the United States has overhauled guidelines for aspirin, recommending that middle-aged and older people no longer take a low dose of the mild analgesic to prevent a first heart attack or stroke, in a move experts hope will make Australians rethink taking aspirin preventatively of their own accord.
Bleeding risks for adults in their 60s and older who haven’t had a heart attack or stroke outweigh potential benefits from the painkiller, the US Preventive Services Task Force said in its draft guidance.
Doctors have long recommended daily low-dose aspirin for many patients who have already had a heart attack or stroke, and the taskforce guidance does not change that advice.
Aspirin is a blood thinner and can help head off heart attacks and strokes by preventing clots from forming in the blood vessels that lead to the heart or brain.
But taking aspirin can also cause major bleeding that can be fatal, especially in older people, said Stephen Nicholls, a world-leading cardiologist and head of Melbourne’s MonashHeart.
“The evidence has frankly been disappointing in terms of it preventing a first heart attack or stroke and the evidence for widespread use of aspirin in everybody of a certain age just isn’t there,” Professor Nicholls said.
He stressed that for people who were already taking aspirin because they were at higher risk of having a heart attack or stroke, the change in guidance does not apply.
“We know that if you’ve had a heart attack, or a stent or a bypass, that the benefits of aspirin are very clear,” he said.
In 2019, Australia overhauled its guidelines recommending that most healthy people should not take aspirin to prevent a first heart attack or cardiovascular disease, warning the risk of serious bleeding outweighs the benefits.
The change in guidance in Australia came amid mounting evidence that use of aspirin in healthy people over 70 did not improve their lifespan and had no measurable impact on a person’s likelihood to suffer heart disease, dementia, stroke, cancer or physical disability.
Professor John McNeil, head of Monash University’s Department of Epidemiology and Preventive Medicine, who led a landmark study of the effectiveness of aspirin, said there was still a misconception among some that the drug could prevent a first-time heart attack.
“From the point of view of most doctors in Australia, they don’t recommend aspirin for primary prevention and there has been a substantial change in medical attitudes to it,” he said.
“But when a change comes in it’s like turning an oil tanker. I think the majority of people have stopped taking it, but of course, not everyone’s convinced by the data.”
He said the medication had never been as a popular in Australia as in the US, where some surveys suggested “between 40 and 50 per cent” took it for primary prevention of heart attacks.
He predicted the shift in clinical guidance in the US would trigger a worldwide change in the use of aspirin.
The US panel said there may be a small benefit for adults in their 40s who have no bleeding risks, but for people in their 50s, the panel softened advice and said evidence of benefit is less clear.
Professor Nicholls urged people not to stop taking the medication before speaking with their doctor.
He said for those aged over 60 the evidence becomes “less and less convincing, and the bleeding risk probably becomes greater and cancels out the benefits.
“In the early studies of aspirin it seemed to be a wonder drug for everybody from a high risk of heart attack and stroke,” he said. “But over the years we’ve become a lot better at treating blood pressure, cholesterol … all the factors that contribute towards the risks of heart attack and stroke, so the benefits of aspirin have become less convincing.”
The recommendation is based on increasing evidence that the risk of serious side effects far outweighs the benefit, and the taskforce posted a draft statement recommending that adults aged 40 to 59 who are at a higher risk of cardiovascular disease – but do not have a history of the disease – decide with their clinician whether to start taking aspirin, based on their individual circumstances.
The recommendation said low-dose aspirin may be considered to prevent heart attacks in adults aged 40 to 70 who are at higher risk of cardiovascular disease but not at increased risk of bleeding.
People at higher risk of heart disease include those with a strong family history of it.
The US panel also plans to retreat from its 2016 recommendation to take aspirin for the prevention of colorectal cancer, guidance that was groundbreaking at the time.
A long-running study involving the Royal Melbourne Hospital, published in The Lancet last year, indicated taking aspirin for just a few years could have a protective effect against the disease, even a decade or more after patients stop taking it.
But the US panel said more recent data had raised questions about the benefits for cancer and more research was needed.
The medical body said the latest advice centres on those younger than 60 who are at high risk of heart disease and for whom a new daily regimen of the mild analgesic might have been a tool to prevent a first heart attack or stroke.
“Our message … is if you don’t have a history of heart attack and stroke, you shouldn’t be starting on aspirin just because you reach a certain age,” said Chien-Wen Tseng, a member of the US Preventive Services Task Force.
Source: The Sydney Morning Herald
