The duo reviewed three randomized controlled trials and found that the risk of major internal bleeding from daily aspirin use outweighs the preventative benefits for those without a history of cardiovascular disease. Aspirin, which is the brand name of acetylsalicylic acid or ASA, can lead to lead to bleeding because it slows clot formation.
“These aren’t nosebleeds or bleeding gums,” Fritsch said in an interview with Folio. “These are major internal bleeds where the patients need hospitalization and perhaps a blood transfusion, so they’re of major clinical, and also personal, significance.”
“This is the most significant practice-changing evidence to come out in the past year,” added Kolber.
Daily aspirin use may also lead to a higher mortality risk
Taking aspirin as a preventative measure for these conditions is a common recommendation of health practitioners which became popular in the 1990s, but Kolber argues it was based on flawed research.
Separate to the review, Kolber’s previous research has shown that daily aspirin use is widespread in Alberta. In a 2013 paper, he and his colleagues sourced survey data from over 800 Albertans over the age of 50. Close to 40% of the respondents reported taking aspirin daily and the majority stated it was for the purpose of lowering their risk of heart complications.
One of the studies in the review involved over 19,000 patients from Australia and the US who were monitored over the course of five years. The key finding was that the effect of 100 mg of aspirin daily imposed a “significantly higher risk of major hemorrhage and did not result in a significantly lower risk of cardiovascular disease than placebo.”
A total of 5.9% of study participants who took aspirin daily died, while 5.2% of those consuming a placebo died. The higher mortality rate in the first group was mainly due to cancer-related deaths, yet previous research has suggested that aspirin improves cancer outcomes. Study team member Leslie Ford from the National Cancer Institute commented in a statement that this finding was “surprising” to the researchers.
But, conventional approach still worth it for some
Kolber and Fritsch wrote that there are evidence-based prevention strategies that should be the go-to for lowering the risk of cardiovascular disease when patients have no history. Quitting smoking is number one on their list, and they cite evidence showing that this can reduce the risk by over 50%. Getting 150 minutes of exercise weekly offers up to a 37% lowered risk, and adopting the Mediterranean diet may lower the risk by 25%.
Speaking to the CBC, Miguel Cainzos Achirica from Johns Hopkins University gave the caveat that this is unlikely to be the end of aspirin as a preventative measure for cardiovascular events. He suggests that more research may be able to classify what kind of people are viable candidates for this form of treatment and how much should be prescribed.
“We just need to learn which patients are going to benefit from aspirin and get no harm or the smallest harm possible,” he says.
Kolber agrees, noting that aspirin should still be considered for those with a history of heart problems: “We really see an aspirin gap,” said Kolber. “There are a lot of people taking aspirin for primary prevention who don’t need it, and there’s a group of people who already have cardiovascular disease who aren’t taking it, and they should be.”