The task force determined that potential harms of adults aged 60 and older using aspirin for prevention outweighed the benefits.
Adults over age 60 would no longer need to start taking a daily aspirin to avoid heart disease even if are high risk, according to draft recommendations released by the US Preventive Services Task Force late Tuesday.
The update is the latest about-face on the role of aspirin, once seen as low-cost way to prevent cardiovascular disease, and more recently colorectal cancer—that recommendation appears headed for reversal as well.
Comments on the recommendations will be received through November 8. US Preventive Service Task Force recommendations carry weight because any recommendation that gets a rating of A or B must be covered without cost-sharing under the Affordable Care Act.
An evidence update prepared for the task force by Kaiser Permanente’s Evidence-based Practice Center outlined why the benefits of aspirins for adults aged 60 and older in preventing heart disease and stroke did not outweigh the risks, namely bleeding.
The revised recommendations say that adults aged 40 to 59 who are at a higher risk for cardiovascular disease (CVD) without a history of CVD should consult with their clinician whether to start taking aspirin, based on their individual circumstances.
“In primary prevention populations, low-dose aspirin reduces major CVD events, MI and ischemic stroke, but also increases major GI bleeding, extracranial bleeding, and intracranial bleeding,” the EPC report said. “Our evidence suggests aspirin is associated with a possible long-term reduction in CRC incidence and mortality based on post-trial period observation, but the results are limited for low-dose aspirin among primary CVD prevention populations.”
The EPC analyzed 13 randomized, controlled trials (RCTs) with a total of 161,680 participants to examine the effectiveness of aspirin for the primary prevention of CVD.
Eleven trials used low-dose (≤100 mg/day) aspirin and found that it reduces the risk of major CVD events by 10%, myocardial infarction (MI) by 11%, and ischemic stroke by 18%, with no differences in CVD or all-cause mortality. Among the 11 trials, absolute risk reductions in major CVD events ranged from 0.08% to 2.5%, and a small subgroup of trials that reported CVD outcomes also reported colorectal cancer (CRC) outcomes. When trials of all doses were pooled, the benefits of aspirin were found to be similar.
Four low-dose aspirin trials focused on recruiting primary CVD prevention populations. When analyzing randomized trial periods, these trials found no statistically significant association between aspirin and CRC incidence.
Two low-dose aspirin RCTs in primary CVD prevention populations reported CRC mortality during the trial period and showed “results concerning for possible harm.” Another similar trial found a statistically significant increase in CRC mortality in older adults.
Three primary CVD prevention trials with a mean daily aspirin dose ranging from 75mg to 500mg showed an association between aspirin and decreased risk of CRC mortality.
In these trials, low-dose aspirin was associated with a 31% increase in intracranial bleeding events and an absolute increase ranging from -0.2% to 0.4%. For extracranial bleeding events, there was a 53% percent increase and an absolute increase ranging from 0.2% to 0.9%.
“There is no compelling evidence to suggest that aspirin has a different relative CVD benefit or bleeding risk in specific populations defined by age, sex, race and ethnicity, diabetes status, or baseline 10-year CVD risk,” the report said. “Aspirin’s CVD benefits appear to begin within the first 1-2 years of administration and the bleeding harms begin soon after aspirin initiation; there are limited data for more precise time increments or longer durations.”
Aspirin has been in the spotlight for several years at major scientific meetings of cardiologists. In 2019, the American College of Cardiology changed its guidelines to say that low-dose aspirin should not be given to adults routinely to prevent atherosclerotic cardiovascular disease once patients reach age 70, and it should not be given to any adult with bleeding risk. For patients who have had a heart attack—when aspirin is still recommended—the low-dose or “baby aspirin” is plenty, based on results of the ADAPTABLE study.