Elsevier

American Heart Journal

Volume 199, May 2018, Pages 137-143
American Heart Journal

Clinical Investigation
Risk of cardiovascular events and incident atrial fibrillation in patients without prior atrial fibrillation: Implications for expanding the indications for anticoagulation

https://doi.org/10.1016/j.ahj.2018.02.005Get rights and content

Abstract

Background

There is growing interest in the role for non–vitamin K antagonist oral anticoagulants (NOACs) in patients without atrial fibrillation (AF). We aimed to provide a comprehensive assessment of the risks of ischemic stroke, myocardial infarction (MI), AF, and major bleeding in patients without previously diagnosed AF.

Methods

Using a large US administrative database, we identified 6,495,875 patients ≥50 years between January 1, 2011, and September 30, 2016, who were not diagnosed with AF and were not treated with oral anticoagulants or nonaspirin antiplatelet agents. We assessed the risks by age, sex, the number of risk factors, and the combination of risk factors. We also calculated the number needed to treat or harm based on the untreated risks in our data set and relative risks of NOAC treatment derived from a recent clinical trial.

Results

The event rates were 0.67%/y for ischemic stroke or MI, 0.96%/y for AF, and 0.52%/y for major bleeding. Among patients who had a stroke during follow-up, 84% were not diagnosed with AF at any time, and only 5% were diagnosed with AF before the stroke. Patients who had low number needed to treat for cardiovascular risk reduction (ie, potentially benefiting the most from the addition of NOACs) also had low number needed to harm for major bleeding (ie, facing serious harm).

Conclusions

Patients without diagnosed AF but with certain risk factors were at a particularly high cardiovascular risk and may require new prevention approaches. In addition to the ongoing trials, future trials in other high-risk populations, for example, diabetes and chronic kidney disease, may be warranted.

Section snippets

Data source and study population

We conducted a retrospective cohort analysis using OptumLabs Data Warehouse, which contains privately insured and Medicare Advantage enrollees of all ages and races from all 50 states.8., 9. The data include inpatient, outpatient, and pharmacy claims. A subset of patients with claims data has linked laboratory results and electronic health records (EHRs).

Our cohort consists of patients who were at least 50 years old and had continuously enrolled in medical and pharmacy insurance plans for at

Results

The study population included 6,495,875 patients aged 50 years or older who were not previously diagnosed with AF. Patients' demographic characteristics and medical history are shown in Table I. Over a mean follow-up of 2.26 ± 1.74 years, we observed 46,294 ischemic strokes, 52,229 MIs, 139,511 AFs, 76,328 major bleeds, 18,534 intracranial bleeds, and 102,229 deaths. The event rates were 0.67%/y for ischemic stroke and MI, 0.32%/y for ischemic stroke, 0.36%/y for MI, 0.96%/y for AF, 0.52%/y for

Discussion

Using 6.5 million people and nearly 15 million person-years of follow-up, our study is the first to assess the risk of ischemic stroke, MI, AF, and major bleeding in a large cohort of patients without diagnosed AF in contemporary routine clinical practice. These data will provide context for the recently published COMPASS trial and other forthcoming trials examining the use of NOACs in non-AF populations. The study also yields important insights into the potential benefits and harms from NOAC

Disclosures

Drs Yao, Sangaralingham, Shah, and Noseworthy report no relationshipswith industry. Dr Gersh has consulted for Janssen Pharmaceuticals.

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  • Cited by (0)

    Sources of funding: This study was funded by the Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, which receives no industry funding. The design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication were solely the responsibility of the authors listed.

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