Real-world evidence highlighting the risks and benefits of novel oral anticoagulants (NOCAs) is lacking. This study compared major and clinically relevant non-major (CRNM) bleeding risk and costs among non-valvular atrial fibrillation (NVAF) patients newly treated with apixaban, dabigatran, rivaroxaban, or warfarin. A retrospective analysis of NVAF patients newly treated with apixaban, dabigatran, rivaroxaban, or warfarin was conducted using PharMetrics Plus data from 1/ 2012 - 9/ 2014. Patients were indexed on the date of the first anticoagulant prescription, and were required to be ≥18 years old and have CHA
2
DS
2
-VASc score > 0 and ≥ 1 month of follow-up. Patients were followed until discontinuation (≥30-day gap in treatment), treatment switch, end of continuous enrollment, 1 year post-index, or end of study. Major and CRNM bleeding, and bleeding-related costs were measured. Cox proportional hazards model was used to examine the association between anticoagulants and risk of bleeding and GLM was used to evaluate bleeding-related costs. The study included 24,573 NVAF patients; distributed as apixaban 11.7%, dabigatran 12.0%, rivaroxaban 36.7%, and warfarin 39.6%. Mean age was 64.4 and 66.5% were males. HAS-BLED and CHA
2
DS
2
-VASc scores averaged 2.0 and 2.7, respectively. After adjusting for differences in baseline characteristics, when compared to apixaban patients, rivaroxaban (HR: 1.5;
P
=0.0013) and warfarin (HR: 1.7;
P
<0.0001) patients were more likely to have major bleeding, and dabigatran (HR: 1.3;
P
=0.0030), rivaroxaban (HR: 1.7;
P
<0.0001), and warfarin (HR: 1.4;
P
<0.0001) patients were more likely to have CRNM bleeding. Major bleeding risk was similar between apixaban and dabigatran patients. Major and CRNM bleeding costs, when compared to apixaban patients ($154 and $18), were significantly higher for dabigatran ($457;
P
<0.0001 and $39;
P
<0.0001), rivaroxaban ($420;
P
<0.0001 and $61;
P
<0.0001), and warfarin ($511;
P
<0.0001 and $63;
P
<0.0001) patients. Among anticoagulant-naive moderate-to-high risk NVAF patients encountered in real-world clinical setting, major bleeding was lower with apixaban compared to warfarin and rivaroxaban. Bleeding costs were lower with apixaban compared to alternative NOACs and warfarin.
REAL-WORLD COMPARISON OF MAJOR BLEEDING RISK AMONG UNTREATED NON-VALVULAR ATRIAL FIBRILLATION PATIENTS AND THOSE INITIATING APIXABAN, DABIGATRAN, RIVAROXABAN, OR WARFARIN
