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Clinical Articles, News & Views

Risks of aspirin with oral anticoagulation in patients with AF

Patients with atrial fibrillation (AF) receiving oral anticoagulation (OAC) are often treated with concomitant aspirin (ASA) therapy, even when they do not have cardiovascular disease, according to a study1 published recently in Circulation. Use of OAC and ASA was associated with significantly increased risk for bleeding, say the authors

The Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) registry enrolled 10,126 AF patients from 176 US practices from June 2010 through August 2011. The study population was limited to those on OAC (n=7347). Hierarchical multivariable logistic regression models were used to assess factors associated with concomitant ASA therapy.

Primary outcomes were 6-month bleeding, hospitalisation, ischaemic events, and mortality. Overall, 35% of AF patients (n=2543) on OAC also received ASA. Patients receiving OAC and ASA were more likely to be male (66% versus 53%; P<0.0001) and had more comorbid illness than those on OAC alone.

More than one third of patients (39%) receiving OAC and ASA did not have a history of atherosclerotic disease, yet 17% had elevated Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) bleeding risk scores (≥5). Major bleeding (adjusted hazard ratio, 1.53; 95% confidence interval, 1.20–1.96) and bleeding hospitalisations (adjusted hazard ratio, 1.52; 95% confidence interval, 1.17–1.97) were significantly higher in those on OAC and ASA compared with those on OAC alone. Rates of ischaemic events were low.

These results emphasise the need to carefully determine if and when the benefits of concomitant ASA outweigh the risks in AF patients already on OAC, the authors conclude.


1. Steinberg BA, Kim S, Piccini JP, et al. Use and Associated Risks of Concomitant Aspirin Therapy With Oral Anticoagulation in Patients With Atrial Fibrillation. Circulation 2013;128:721–8.​CIRCULATIONAHA.113.002927

Published on: August 30, 2013

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  • ArrhythmiaAlliance
  • Stars
  • Anticoagulation Europe
  • Atrial Fibrillation Association

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