Aspirin should not be taken to prevent heart disease unless on doctors’ orders, scientists have warned after a major study found the drug “substantially” increases the risk of dangerous bleeds.
A review of 164,225 people in their fifties, sixties and seventies found that regularly taking the inexpensive drug boosts the chances of major bleeding by more than 40 per cent.
Aspirin has long been recommended for patients already known to suffer from heart conditions and those at high risk of stroke, with evidence indicating its blood-thinning qualities render the risk of side-effects worthwhile.
However, the new research by King’s College London suggests that for middle-aged and older people currently in good health, the benefit of regularly taking the drug is not worth the risk of serious bleeding.
Aspirin is not routinely prescribed for “primary prevention” of heart disease or stroke in the UK.
Nevertheless, experts have estimated that tens of thousands of healthy people take the inexpensive drug anyway.
Published in the Journal of the American Medical Association, the study of 53 to 74-year-olds included people taking aspirin, those taking a placebo and those on no treatment at all.
Regular use of aspirin was associated with an 11 per cent lower risk of cardiovascular events such as heart disease, heart attack and stroke.
This means that roughly 250 patients would need to be treated with the medication for five years to prevent a single cardiovascular event.
However, those taking aspirin were 43 per cent more likely to suffer a major bleeding episode than those not using the drug.
Dr Sean Zheng, who led the research, said: “This study demonstrates that there is insufficient evidence to recommend routine aspirin use in the prevention of heart attacks, strokes and cardiovascular deaths in people without cardiovascular disease.”
Meanwhile Professor Stephen Evans, from the London School of Hygiene & Tropical Medicine, said: “The message for healthy patients is that taking aspirin has a small benefit to prevent heart disease but also at least as large a harm in terms of serious bleeding.
“For some individual patients the balance may tip more clearly in either direction.”
After Alzheimer’s, heart disease is Britain’s second biggest killer, claiming roughly 153,300 lives a year of approximately seven million patients living with one or more of the conditions, which are closely linked to poor lifestyle.
Last night the Royal College of GPs (RCGP)said patients who regularly take aspirin “should not panic”, but should talk to their family doctor if they are concerned about the drug.
“Aspirin can be an inexpensive and effective drug for reducing risks of recurrence in patients who have suffered a stroke or heart attack, but we have known for many years that there are risks and side effects involved with its long-term use, and this study highlights the importance of managing its use carefully and effectively,” said Professor Helen Stokes-Lampard, RCGP chair.
Experts have previously warned people who have been self-medicating with daily low-dose aspirin against stopping abruptly in order to avoid rebound “stickiness” of the blood.
Instead, they recommend reducing the dose gradually over a month to six weeks.
“Aspirin use requires discussion between the patient and their physician, with the knowledge that any small potential cardiovascular benefits are weighed up against the real risk of severe bleeding,” said Dr Zheng.
Kevin McConway, emeritus professor of applied statistics at the Open University, said future research should concentrate on methods of enabling GPs to recommend aspirin on a more personal basis.
“Ideally it would help to know whether some people have characteristics that make aspirin a good choice for them, while it would be better for others to avoid it,” he said.