New draft recommendations from the U.S. Preventive Services Task Force (USPSTF) on the use of aspirin for the primary prevention of cardiovascular disease (CVD) have been released and appear to limit the population in which it should be considered.
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“The USPSTF concludes with moderate certainty that aspirin use for the primary prevention of CVD events in adults ages 40 to 59 years who have a 10% or greater 10-year CVD risk has a small net benefit,” the recommendation notes. They conclude that for these patients, the decision to use aspirin “should be an individual one.”
“Persons who are not at increased risk for bleeding and are willing to take low-dose aspirin daily are more likely to benefit,” they note.
For older individuals, however, the task force concludes.
The new recommendations were posted online Oct. 12 and will be available for public comment until November 8. Once it is finalized, the recommendation will replace the 2016 USPSTF recommendation on aspirin use to prevent CVD and colorectal cancer (CRC), they note.
In that document, the task force recommended initiating low-dose aspirin for the primary prevention of both CVD and CRC in adults 50-59 years of age who had a 10% or greater 10-year CVD risk, were not at increased risk for bleeding, had a life expectancy of at least 10 years, and were willing to take daily low-dose aspirin for at least 10 years, with the decision to start being an individual one.
For older and younger patients, they found at that time that the evidence was “insufficient to assess the balance of benefits and harms of initiating aspirin use for the primary prevention of CVD and CRC in adults younger than age 50 years or adults aged 70 years or older.”
In the new draft document, “the USPSTF has changed the age ranges and grades of its recommendation on aspirin use.” Besides the recommendations for CVD prevention, they have also changed the previous recommendation of aspirin for the prevention of CRC given evidence generated from large primary CVD prevention trials.
“Based on new analyses of the evidence from primary CVD prevention populations, longer-term follow-up data from the Women’s Health Study (WHS) (JE Buring, personal communication, November 23, 2020), and new trial evidence, the USPSTF concluded that the evidence is inadequate that low-dose aspirin use reduces CRC incidence or mortality,” it states.
Optimum dose
On the optimum dose for primary CVD prevention, the task force says the benefit appears similar for a low dose (≤100 mg/d) and all doses that have been studied in CVD prevention trials (50 to 500 mg/d). “A pragmatic approach would be to use 81 mg/d, which is the most commonly prescribed dose in the United States,” it states.
The USPSTF recommends using the ACC/AHA Pooled Cohort Equations to estimate cardiovascular risk but it points out that these equations are imperfect for risk prediction at the individual level, and suggests using these risk estimates as a starting point to discuss with appropriate candidates their desire for daily aspirin use. The benefits of initiating aspirin use are greater for individuals at higher risk for CVD events (eg, those with >15% or >20% 10-year CVD risk), they note.
“Decisions about initiating aspirin use should be based on shared decision-making between clinicians and patients about the potential benefits and harms. Persons who place a higher value on the potential benefits than the potential harms may choose to initiate low-dose aspirin use. Persons who place a higher value on the potential harms or on the burden of taking a daily preventive medication than the potential benefits may choose not to initiate low-dose aspirin use,” the task force says.
It also points out that the risk for bleeding increases modestly with advancing age. “For persons who have initiated aspirin use, the net benefits continue to accrue over time in the absence of a bleeding event. The net benefits, however, become smaller with advancing age because of an increased risk for bleeding, so modeling data suggest that it may be reasonable to consider stopping aspirin use around age 75 years,” it states.