Clinician Article

A Meta-analysis of Aspirin for the Primary Prevention of Cardiovascular Diseases in the Context of Contemporary Preventive Strategies.

  • Shah R
  • Khan B
  • Latham SB
  • Khan SA
  • Rao SV
Am J Med. 2019 May 30. pii: S0002-9343(19)30448-6. doi: 10.1016/j.amjmed.2019.05.015. (Review)
PMID: 31153866
Read abstract
  • Family Medicine (FM)/General Practice (GP)
    Relevance - 7/7
    Newsworthiness - 5/7
  • General Internal Medicine-Primary Care(US)
    Relevance - 7/7
    Newsworthiness - 5/7
  • Internal Medicine
    Relevance - 7/7
    Newsworthiness - 5/7
  • Public Health
    Relevance - 7/7
    Newsworthiness - 5/7
  • Cardiology
    Relevance - 6/7
    Newsworthiness - 4/7
  • Geriatrics
    Relevance - 6/7
    Newsworthiness - 4/7
  • Endocrine
    Relevance - 5/7
    Newsworthiness - 4/7


BACKGROUND: The role of aspirin for primary prevention of cardiovascular diseases remains controversial, particularly in the context of contemporary aggressive preventive strategies.

METHODS: Relevant randomized clinical trials were included, and risk ratios (RRs) were calculated using random-effects models. Additional moderator analyses were performed to compare the pooled treatment effects from recent trials (those reported after the guidelines of the National Cholesterol Education Program Third Adult Treatment Panel were published in 2001; thus, conducted on the background of contemporary preventive strategies) to the results of older trials.

RESULTS: Data from 14 randomized controlled trials involving 164,751 patients were included. Aspirin use decreased myocardial infarction risk by 16% compared with placebo (RR 0.84; 95% confidence interval [CI], 0.75-0.94); however, in the moderator analyses, aspirin was not associated with a decreased risk of myocardial infarction in recent trials, but was in older trials (P-interaction = .02). Overall, aspirin use significantly increased the occurrence of major bleeding (RR 1.49; 95% CI, 1.32-1.69) and hemorrhagic stroke (RR 1.25; 95% CI, 1.01-1.54). In moderator analyses, the risk of major bleeding (P-interaction = .12) or hemorrhagic stroke (P-interaction = .44) with aspirin was not significantly different between the older and new trials. Differences between aspirin and placebo in the risks for all-cause stroke, cardiac death, and all-cause mortality were not found.

CONCLUSIONS: In the context of contemporary primary prevention guidelines, the effect of aspirin on myocardial infarction risk was significantly attenuated, whereas its major bleeding and hemorrhagic stroke complications were retained. Therefore, in contemporary practice, routine use of aspirin for the primary prevention of cardiovascular events may have a net harmful effect.

Clinical Comments


For primary prevention of cardiovascular disease, aggressive risk factor modification and lifestyle changes are more useful than aspirin for most patients, except those adults at very high risk for ASCVD. This meta-analysis reflects the recommendations of professional society guidelines regarding the use of aspirin in primary prevention.


This breaks the myth of the magical power of ASA!


There is a lack of patient-specific data that would clarify whether specific risks or preventative treatments were used and limits the ability to compare across variable outcomes. This study confirms the current bias against liberal use of primary prevention with aspirin, but not whether the level of risk threshold could be found or whether mitigating bleeding risk is possible.

General Internal Medicine-Primary Care(US)

Very nice meta-analysis comparing the benefits and risks of aspirin in newer and older studies.

General Internal Medicine-Primary Care(US)

This article may not be news to all providers, but it is very important. This whole ASA-a-day is no longer the way to go in low- or no-risk people.

General Internal Medicine-Primary Care(US)

There are few well-done studies that are as directly relevant to the day-to-day world of the primary care physician as this one.


The meta-analysis by Shah et al adds a breakdown between old (pre-NCEP-ATP III) and new (post-NCEP-ATP III) studies for MI and major bleeding. New studies, which followed a more contemporary cohort and prevention approach, in aggregate did not show a statistically significant reduction in MI compared with older studies. It also shows a marginally significant reduction in ischemic stroke, but not all strokes; a non-significant overall reductions in CV and total mortality; and a statistically significant increase in risk for major bleeding, which was not different between new and old studies. This study reinforces the conclusion that ASA is not effective for primary prevention of MI even in younger patients. It contradicts the recommendations of the USPSTF, but is consistent with the European Society of Cardiology. Because this topic is so controversial and primary prevention of CVD with ASA is so prevalent, it is reasonable to consider one final meta-analysis to emphasize the inappropriateness of ASA for routine primary prevention of coronary events.

Public Health

For a cardiologist who prescribes aspirin everyday, this article is very important and useful. In modern clinical practice, aspirin for primary prevention is not justified and could cause substantial bleeding risk.

Register for free access to all Professional content

Want the latest in aging research? Sign up for our email alerts.
© 2012 - 2019 McMaster University | 1280 Main Street West | Hamilton, Ontario L8S4L8 | +1 905-525-9140 | Terms Of Use