Aspirin may benefit some people without CVD

The benefits of aspirin outweigh its bleeding harms for some patients without cardiovascular disease (CVD), suggests a New Zealand study.

An individualized benefit­–harm analysis was performed based on sex-specific risk scores and estimates of the proportional effect of aspirin on CVD and major bleeding from a 2019 meta-analysis. A total of 245,028 individuals (43.6 percent women) aged 30–79 years without established CVD who had their CVD risk assessed between 2012 and 2016 were included.

The investigators calculated the net effect of aspirin for each participant by subtracting the number of CVD events likely to be prevented (CVD risk score x proportional effect of aspirin on CVD risk) from the number of major bleeds likely to be caused (major bleed risk score x proportional effect of aspirin on major bleeding risk) over 5 years.

A net benefit from aspirin treatment for 5 years was expected in 2.5 percent of women and 12.1 percent of men if one CVD event was assumed to be equivalent in severity to one major bleed. If one CVD event was assumed to be equivalent to two major bleeds, then aspirin was likely to benefit 21.4 percent of women and 40.7 percent of men.

Compared with net harm subgroups, net benefit subgroups had higher baseline CVD risk, higher levels of most established CVD risk factors and lower levels of bleeding-specific risk factors.

This study had certain limitations, such as uncertain risk scores and effect estimates, nonconsideration of the effects of aspirin on cancer outcomes and the failure to assess applicability to non-New Zealand populations.