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5MinuteConsult Journal Club 

Aspirin NOT for Primary Prevention 


Nudy M, Cooper J, Ghahramani M, et al. Aspirin for Primary Atherosclerotic Cardiovascular Disease Prevention as Baseline Risk Increases: A Meta-Regression Analysis. Am J Med. 2020 Sep;133(9):1056-1064. doi: 10.1016/j.amjmed.2020.04.028. Epub 2020 May 20. PMID: 32445718 

Study Summary

This is a meta-regression analysis of randomized, controlled trial data to determine the benefits and harms of aspirin when used for primary prevention.

It found aspirin did lower ASCVD risk (4.7 vs. 5.3 events per 1000 patient-years; RR 0.86; 95% CI, 0.79-0.92). Unfortunately, this benefit was offset by the increased risk of “major” GI bleeding (2.5 vs. 1.8 events per 1000 patient-years; RR 1.41; 95% CI, 1.29-1.54). This risk was significant enough to nullify the benefit of aspirin. It also found using aspirin for primary prevention in higher-risk patients provided no additional benefit, meaning the aspirin’s influence did not increase as the patients’ risk increased. 


The benefit of aspirin for the primary prevention of ASCVD is limited due to its adverse risks, and those in higher risk groups did not benefit. 

Stats Refresher 

Regression analysis is a way to look at the influence of “independent variable” (in this case, aspirin) on a “dependent variable” (in this study, ASCVD). It helps predict the influence of some action on an outcome. 

Contributed by Frank J. Domino, MD, March 31, 2021