A study found that 2.5% of women and 12.1% of men without established cardiovascular disease (CVD) were likely to derive net benefit from five years of aspirin treatment.
Researchers in New Zealand used a 2019 meta-analysis to model individual benefits versus harms of aspirin use based on sex-specific risk scores and estimates of the proportional effect on CVD and major bleeding.
Among 245,028 people ages 30 to 79 years without established CVD who had their CVD risk assessed between 2012 and 2016, researchers calculated the net effect of aspirin for each participant by subtracting the number of CVD events likely to be prevented (CVD risk score × proportional effect of aspirin on CVD risk) from the number of major bleeds likely to be caused (major bleed risk score × proportional effect of aspirin on major bleeding risk) over five years. Results were published by Annals of Internal Medicine on Sept. 17.
If one CVD event was assumed to be equivalent in severity to one major bleed, 2.5% of women and 12.1% of men were likely to have a net benefit from aspirin treatment for five years, a rate that increased to 21.4% of women and 40.7% of men if one CVD event was assumed to be equivalent to two major bleeds.
The study authors noted that the proportion of people classified as deriving net benefit from aspirin under these assumptions ranged from 0.1% to 60.0% of women and 1.9% to 77.9% of men when the upper and lower limits of the 95% CIs of the proportional effect of aspirin on CVD and major bleeding were used instead of the point estimates.
“In conclusion, some persons without CVD are likely to derive net benefit from aspirin,” authors wrote. “They could be identified by using a personalized benefit–harm analysis, and sharing the findings of such an analysis with patients might support more informed decision making.”
An editorial noted that patients older than age 79 were not included in the study and that establishing firm, evidence-based recommendations for aspirin use in primary prevention is difficult, given the diversity of research findings. “It seems reasonable to recommend aspirin for the primary prevention of CVD in select patients, including those who are at high risk for CVD, provided that the bleeding risk is low, as evidenced by a history of bleeding and comorbid conditions,” the editorialist wrote.