Higher bleeding rate in AF patients treated with OACs and aspirin

Use and Associated Risks of Concomitant Aspirin Therapy With Oral Anticoagulation in Patients With Atrial Fibrillation: Insights From the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) Registry.

Literature - Steinberg BA, Kim S, Piccini JP,et al.; ORBIT-AF Investigators and Patients - Circulation. 2013 Aug 13;128(7):721-8

Steinberg BA, Kim S, Piccini JP, et al.; ORBIT-AF Investigators and Patients
Circulation. 2013 Aug 13;128(7):721-8. doi: 10.1161/CIRCULATIONAHA.113.002927


Oral anticoagulant (OAC) therapy is the central component of treatment of atrial fibrillation (AF) in patients at risk of stroke. Many patients with AF may also receive antiplatelet therapy to treat concomitant atherosclerotic cardiovascular disease [1]. It is however unclear whether there is an additional benefit of antiplatelet therapy when added anticoagulation in patients with AF.
European guidelines support the temporary use of more aggressive concomitant antiplatelet therapy  in patients at a low risk of bleeding. US guidelines however, are more reserved [2,3]. Little information is available on the actual use of concomitant antiplatelet therapy and OAC in AF patients in the US, thus the risks of such therapeutic combination in community practice remains unclear.
Data from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) [4] was used to investigate implementation of aspirin (ASA) therapy in patients with AF receiving OAC and associated clinical outcomes. Data of 7347 patients receiving OAC were included in this analysis, of which 35% (n=2543) received concomitant ASA therapy.

Main results

  • Patients receiving OAC+ASA were slightly younger, more often male, and had more medical co-morbidities than patients receiving OAC alone. Patients receiving combination therapy were more likely to have new-onset (4.6% vs. 3.8%) or paroxysmal (47% vs. 45%) AF, rather than long-standing persistent AF (30% vs. 33%).
    Stroke risk scores were higher in patients receiving OAC+ASA than in patients on OAC monotherapy (CHADS2>2 in 79% vs. 72% of patients), while ATRIA bleeding risk scores did not differ among groups.
  • The strongest positive effect estimates for use of concomitant ASA were seen for a history of coronary artery disease (adjOR: 2.23, 95%CI: 1.82-2.73), previous maze procedure (adjOR: 1.56, 95%CI: 1.05-2.32), any previous drug-eluting stent (adjOR: 1.53-95%CI: 1.17-2.01) and previous stroke or TIA (adjOR: 1.45, 95%CI: 1.25-1.67).
  • Major bleeding and bleeding hospitalisation rates were significantly higher in patients receiving OAC+ASA. There were more intracranial haemorrhage events in OAC+ASA group (10 vs. 6, 0.43% vs. 0.14%, P=0.02).
    After correction for baseline characteristics, major bleedings (HR: 1.53, 95%CI: 1.20-1.96) and bleeding hospitalisation (HR: 1.52, 95%CI: 1.17-1.97) are more likely in patients on OAC+ASA than in patients on OAC monotherapy.  


35% patients with AF on OAC therapy also received ASA, although at least one third of these people did not have a history of atherosclerotic disease. On the other hand, patients with AF and known cardiovascular disease often only receive OAC. Concomitant use of OAC and aspirin was associated with a higher risk for bleeding. Clinicians need to carefully estimate for each patient whether the risks of combined therapy outweigh the benefit. Definite insights on the benefit or harm of these therapeutic strategies will need to be confirmed by adequately powered prospective clinical studies.


1. Lopes RD, Pieper KS, Horton JR, et al. Short- and long-term outcomes following atrial fibrillation in patients with acute coronary syndromes with or without ST-segment elevation. Heart. 2008;94:867–873.
2. Camm AJ, Kirchhof P, Lip GY, et al. Guidelines for the management of atrial fibrillation: the Task
Force for the Management of Atrial Fibrillation of the European Society of Cardiology (ESC). Eur Heart J. 2010;31:2369–2429.
3. Fuster V, Ryden LE, Cannom DS, et al. 2011 ACCF/AHA/HRS focused updates incorporated into the ACC/AHA/ESC 2006 guidelines for the management of patients with atrial fibrillation: a report of the American
College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. 2011;123:e269–e367.
4. Piccini JP, Fraulo ES, Ansell JEet al. Outcomes Registry for Better Informed Treatment of Atrial Fibrillation: rationale and design of ORBIT-AF. Am Heart J. 2011;162:606–612.e1.

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