Abstract Number: OC 71.3
Meeting: ISTH 2022 Congress
Background: For patients anticoagulated with a direct oral anticoagulant (DOAC) or warfarin for the indications of non-valvular atrial fibrillation and/or venous thromboembolism, adding concomitant aspirin (ASA) therapy can increase bleeding risk with uncertain antithrombotic benefit. It is unclear if outcomes with apixaban or rivaroxaban and ASA differ from warfarin and ASA.
Aims: To assess bleeding and thrombotic event rates for apixaban and rivaroxaban with aspirin as compared to warfarin and aspirin.
Methods: Within the six-center Michigan Anticoagulation Quality Improvement Initiative (MAQI2), we analyzed registry data for warfarin or DOAC treated patients with atrial fibrillation and/or venous thromboembolism without a clear indication for concomitant ASA (e.g., recent myocardial infarction or history of heart valve replacement) who were taking ASA. Warfarin+ASA treated patients were propensity matched to DOAC+ASA treated patients who had at least 3 months of follow-up data. The primary outcome was bleeding. Secondary outcomes included episodes of thrombosis, healthcare utilization, and death. Event rates were compared using Poisson regression. Residual differences between matched groups were included in the Poisson regression models as appropriate.
Results: 1,328 warfarin+ASA patients were matched to 872 on apixaban+ASA and 377 on rivaroxaban+ASA. Patient demographics, co-morbidities, indication for anticoagulation, history of bleeding or clotting, medications, and duration of follow-up were fairly similar after matching. Patients were followed for a mean (standard deviation) of 23.8 months (26.0 months) for warfarin versus apixaban and 24.5 months (29.4 months) for warfarin versus rivaroxaban. Bleeding and thrombotic outcomes between apixaban+ASA were similar to warfarin+ASA (Table 1), aside for more emergency room visits for bleeding with warfarin+ASA. We observed increased bleeding and thrombotic events with rivaroxaban+ASA compared to warfarin+ASA (Table 2).
Conclusion(s): Patients treated with rivaroxaban+ASA may experience worse clinical outcomes compared to warfarin+ASA while outcomes between apixaban+ASA and warfarin+ASA seem similar.
To cite this abstract in AMA style:Schaefer J, Errickson J, Kong X, Ali M, Edupuganti S, Haymart B, Kaatz S, DeCamillo D, Kline-Rogers E, Shah V, Sood S, Froehlich J, Barnes G. Bleeding Outcomes for Patients on Anticoagulant and Antiplatelet Therapy [abstract]. https://abstracts.isth.org/abstract/bleeding-outcomes-for-patients-on-anticoagulant-and-antiplatelet-therapy/. Accessed September 27, 2022.
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