Whether Aspirin Is Safe for Primary Prevention

Although aspirin use for primary prevention in patients without cardiovascular disease (CVD) may confer some benefits, it is not without risk, according to new research.1

A systematic review and meta-analysis published in JAMA that assessed the effects of aspirin for primary prevention in patients without CVD found that aspirin use was associated with a lowered risk of cardiovascular events, but an elevated bleeding risk.1

Currently, aspirin plays an important role in the acute management of vascular events, for use following certain procedures, and for secondary CVD prevention.2 Until now, the use of aspirin as a primary prevention measure has been heavily debated due to the potential risks, prompting researchers to investigate it further.

The analysis, which was performed by Sean L. Zheng, BM, BCh, MA, MRCP, and Alistair J. Roddick, BSc, of Kings College London, included 13 trials (N = 164,225) and 1,050,511 participant-years of follow-up.

Specifically, they found that aspirin use was associated with a significantly reduced risk of developing the composite cardiovascular outcome of cardiovascular mortality, nonfatal myocardial infarction, and nonfatal stroke compared with non-use (57.1 vs 61.4 per 10,000 participant-years, respectively).

For major bleeding events, however, aspirin use was found to be associated with an elevated risk compared with non-use (23.1 vs 16.4 per 10,000 participant-years, respectively).

These findings suggest that the use of aspirin for primary prevention should be determined only after careful selection and consideration of individual patient factors, as well as other additional interventions including smoking cessation, blood pressure control, and control of lipid levels, wrote J. Michael Gaziano, MD, MPH, of Brigham and Women’s Hospital in Boston, in an accompanying editorial.2

With this in mind, Consultant360 spoke with lead study author Dr Zheng about how clinicians can apply these findings in practice when determining what role aspirin might play for their patients.

Sean L. Zheng, BM, BCh, MA, MRCP, is an academic clinical fellow in the Department of Cardiovascular Medicine at King’s College Hospital NHS Foundation Trust in London, England.

Consultant360: What are some common misconceptions among clinicians about aspirin use in their patients?

Dr Zheng: I think there are clinicians who share views across the whole spectrum. There are some clinicians who certainly would recommend aspirin to prevent heart attacks and strokes, particularly in those who are deemed to be at higher risks of these events. Alternatively, there will be others who assume that the absolute effects of aspirin are neutral or, at best, very small. I believe that the results of this study can be used by both camps to justify their decisions. In the end, the final decision rests with the patient and their own views on whether they perceive the potential benefits to be worth the certain risks.

C360: What compelled you to study the effects of aspirin as a primary prevention measure in patients without CVD?

Dr Zheng: The use of aspirin in primary prevention of CVD is controversial. Despite uncertainties in the body of evidence, a large proportion of adults continue to take aspirin on a regular basis with the expectation that it prevents heart attacks and strokes. This number has been estimated to be almost 50% in the United States, rising to over 60% to 70% in those who are at higher cardiovascular risk. A number of trials published in 2018 provided further uncertainty about the effectiveness and safety of aspirin in people who have not suffered from CVD. 

C360: How should the findings from your systematic review and meta-analysis inform clinical practice?

Dr Zheng: I believe that the results of our study should be used to provide evidence against the routine use of aspirin for the primary prevention of CVD. Before recommending aspirin for a patient who has no history of CVD, they should be mindful that the absolute benefits and risks are evenly balanced. This message must be conveyed to the patient so that there is a realistic expectation that they may be as likely to have a major bleeding event as they are to not have a heart attack or stroke. 

C360: What are the next steps in your research?

Dr Zheng: The next steps in our research are to try and identify potential risk scores or markers that can be used to identify subgroups of patients who may disproportionately benefit from aspirin use. Such groups of patients could be expected to experience the beneficial effects of aspirin with minimized adverse effects.

—Christina Vogt


1. Zheng SL, Roddick AJ. Association of aspirin use for primary prevention with cardiovascular events and bleeding events: a systematic review and meta-analysis. JAMA. 2019;321(3):277-287. doi:10.1001/jama.2018.20578.

2. Gaziano JM. Aspirin for primary prevention: clinical considerations in 2019. JAMA. 2019;321(3):253-255. doi:10.1001/jama.2018.20577.

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