Don't take Aspirin to prevent first heart attack or stroke, Alberta physicians advise

New research suggests many Canadians should rethink the old adage of taking a low dose of Aspirin daily to prevent heart attacks and strokes.

Paul Fritsch, a family medicine resident at the University of Calgary, and Michael Kolber, a family medicine professor at the University of Alberta, reviewed three randomized controlled trials from 2018. Their conclusions, first distributed through the Alberta College of Family Physicians, appeared recently in the medical journal Canadian Family Physician.

The three studies followed patients without pre-existing cardiovascular disease who took either Aspirin or a placebo for four to seven years. Each study had similar results.

"If there was any potential benefit of decreasing a future cardiovascular event, it was offset by these major clinical bleeds," Kolber said Wednesday in an interview with CBC's Radio Active.

One study followed more than 19,000 elderly patients in the United States and Australia for about five years. It found the patients who took 100 mg of Aspirin per day had a significantly higher risk of major hemorrhage but not a significantly lower risk of cardiovascular disease than the placebo group.

Taking Aspirin, the brand name for acetylsalicylic acid or ASA, can sometimes lead to bleeding because the drug helps slow the formation of clots. 

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Kolber's own research suggests many Albertans are still taking Aspirin every day as a preventative measure.

For a 2013 paper, he surveyed 807 patients who were 50 years of age or older at two family medicine clinics in Alberta, finding that nearly 40 per cent of them reported taking ASA every day. Most of the patients who took the drug did so for cardiovascular prevention.

Old advice still applies for some patients

Daily low-dose Aspirin is still thought to be effective for people who have had heart problems or think they might be having a stroke or heart attack.

"That evidence is still strong," Kolber said.

Healthy adults, though, should speak with their health care professionals and consider alternatives, he said.

Evidence-based prevention strategies recommended by Kolber's paper include exercising for 150 minutes per week, eating a Mediterranean diet and giving up smoking.

A guideline from the American College of Cardiology Foundation and the American Heart Association said Aspirin should be used infrequently in routine primary prevention for cardiovascular disease.

Those concerned about cholesterol levels could consider taking a cholesterol-lowering drug, Kolber said.

Miguel Cainzos Achirica, a cardiologist and researcher at Johns Hopkins University in Baltimore, said despite all the bad press around Aspirin recently, scientists still believe it can play a role in preventing cardiovascular events for some people.

"We just need to learn which patients are going to benefit from Aspirin and get no harm or the smallest harm possible," he said.

"We don't think this is the death of Aspirin."