Daily aspirin offers little to no benefit for most adults trying to prevent heart disease, new report says

Taking low-dose aspirin every day to prevent a heart attack or stroke provides little to no benefit to people without cardiovascular disease but could instead increase the risk of dangerous bleeding, a new report from the U.S. Preventive Services Task Force says.

For adults ages 60 and up who don’t have cardiovascular disease or aren’t at high risk of developing it, the task force determined there was no benefit to starting aspirin if they are not already on it. Among adults 40 to 59 years old, the task force, a volunteer group of medical experts, concluded “with moderate certainty” that there was a small net benefit to taking low-dose aspirin among those who have a 10% or higher risk of developing heart disease in a 10-year period. It’s up to those individuals and their doctors to decide whether to take aspirin, the task force concluded.

The new recommendation is an update to the task force’s 2016 report, which recommended low-dose aspirin for individuals ages 50 to 59 (a decade older than the new guidelines) with 10% or greater 10-year risk of developing cardiovascular disease and who did not have bleeding risk or a life expectancy of less than 10 years. In those ages 60 to 69 who met that 10% risk threshold, the 2016 recommendation left the choice of whether to begin aspirin up to individuals and their doctors.

In the last several years, new evidence from various clinical trials has “cast doubt over the use of ‘aspirin for all,'” said Carlos G. Santos-Gallego, a cardiologist at The Mount Sinai Hospital in New York City. Mounting evidence suggests that the higher a person’s risk of getting heart disease and the lower their risk of bleeding, the more they benefit from taking aspirin, he said. Bleeding risk, however, increases with age.

Those who benefit most from taking a daily low-dose aspirin tablet are people with greater than a 15% or 20% risk for developing cardiovascular disease over a 10-year period, according to the recommendation, published in JAMA on Tuesday. The key recommendation applies only to those 40 years and older who don’t have cardiovascular disease or signs of it, who have no history of cardiovascular disease, who are not taking aspirin for another condition, and who aren’t at increased risk for bleeding. As an anticoagulant, aspirin can increase the risk of bleeding after an injury. The recommendations do not apply to people who have cardiovascular disease, or who use aspirin after having had a heart attack, stroke, or other cardiovascular issue.

To meet the 10% or greater risk threshold set by the task force, “you’ve got to have a lot of risk factors,” said cardiologist Steven Nissen, chief academic officer of the Heart, Vascular & Thoracic Institute at the Cleveland Clinic. “Not very many people, even with these recommendations, are going to qualify.”

Nissen was not involved in the updated recommendation, but served on an FDA advisory panel nearly two decades ago that arrived at a similar conclusion when Bayer, the maker of aspirin, asked the FDA to label the drug for prevention of cardiovascular disease in people who didn’t already have it. That panel said no.

Since then, “clinical inertia” — the slow adoption of new practices by doctors — poor communication, and unclear guidance have meant aspirin is still commonly used by those who are not at major risk of developing cardiovascular disease, Nissen said. Over the decades, several groups, such as the American Academy of Family Physicians, the American College of Cardiology, and the American Heart Association, as well as the FDA itself, have disagreed on who low-dose aspirin can help, and how much it can help them. The task force still leaves the decision of whether to use aspirin for prevention up to individuals and their doctors — especially for those 40 to 59 years old — but refutes the old idea that the drug is totally harmless, Nissen said.

“Group by group, bit by bit, people have come around to the idea that the risks are about equivalent to its benefits for most people,” Nissen told STAT.

To arrive at its recommendation, the task force reviewed 13 randomized clinical trials on the benefits and risks of aspirin use for preventing the development of cardiovascular disease or dying from it. They found aspirin use was associated with a lower risk of heart attack and stroke but not cardiovascular mortality or all-cause mortality.

Part of the review also showed that low-dose aspirin use was linked to a 58% increase in major gastrointestinal bleeding and an increase in bleeding into the brain when compared to people not taking aspirin. “If you’re taking an aspirin a day and you get in a motor vehicle accident, you’re going to bleed more,” Nissen said.

The stakes are high: Heart disease is the leading cause of death in the United States, and is the cause of more than 1 in 4 deaths — killing more Americans than cancer, Covid-19, and Alzheimer disease in 2021. More than 1 million Americans have their first heart attack or stroke each year, statistics from the American Heart Association show.

Black people are more likely to develop cardiovascular disease than non-Black people, although the report notes race is “a social construct and an imperfect proxy for social determinants of health and the effects of structural racism,” so some calculations of risk may be inaccurate. Sex is another risk factor. Those assigned male at birth bear the brunt of cardiovascular disease and its effects on quality of life, but those assigned female at birth are more likely to die from cardiovascular issues, including stroke, which they experience later in life than men.

The task force’s analysis found that the benefits of aspirin for preventing cardiovascular disease is about the same for doses from 50 milligrams to 500 milligrams. The dose recommended by the USPSTF is 81 milligrams, the most commonly prescribed amount in the United States. The task force continued to support its position that there is little evidence that low-dose aspirin prevents colorectal cancer, and that as with cardiovascular disease the harms may outweigh the benefits.

The risk of gastrointestinal bleeding, bleeding into the brain (the cause of hemorrhagic strokes), or bleeding from other causes increases with age, and so could be made worse by aspirin use. People who smoke, along with those with diabetes, a history of gastrointestinal problems, liver disease, or high blood pressure are also at higher risk of bleeding, so those factors should be taken into consideration when deciding whether to begin taking an aspirin a day. No matter the case, the task force recommends consulting a doctor before starting or stopping an aspirin regimen.