A Novel Bleeding Risk Stratification Scheme in Japanese Patients with Non-valvular Atrial Fibrillation: The J-RISK AF study

Background Oral anticoagulants (OAC) reduce the risk of ischemic stroke, but may increase the risk of major bleeding in non-valvular atrial fibrillation (NVAF) patients. Various risk scores, such as HAS-BLED, ATRIA, and ORBIT, have been proposed to assess the risk of major bleeding in NVAF patients receiving OAC. However, limited data are available on bleeding risk stratification in Japanese NVAF patients. Methods Of the 16,098 NVAF patients from the J-RISK AF study, the combined data of the five major AF registries in Japan (J-RHYTHM Registry, Fushimi AF Registry, Shinken Database, Keio interhospital Cardiovascular Studies, and Hokuriku-Plus AF Registry), we analyzed 11,539 patients receiving OAC (median age, 71 years; female, 39.6%; median CHADS 2 score, 2). Multivariable Cox-hazard proportional analysis was performed to explore significant risk factors for major bleeding. Using those factors, we developed a novel bleeding risk stratification scheme and compared its predictive performance with previously reported risk scores. Results During the 2-year follow-up period, major bleeding occurred in 274 patients (1.3% per patient-year). On multivariable analysis, advanced age, uncontrolled hypertension, history of bleeding, anemia, thrombocytopenia, and concomitant antiplatelet agents were significantly associated with higher incidence of major bleeding. We developed a novel risk stratification system, J-RISK bleeding score, that had good predictive performance (C-statistics 0.67) for major bleeding. The predictive performance of our score was better than previous scores. Conclusion Our findings suggest that our novel risk stratification system, the J-RISK bleeding score, is more useful than previous score systems for Japanese NVAF patients receiving OAC.