External Validation of the ORBIT Bleeding Score and the HAS-BLED Score in Nonvalvular Atrial Fibrillation Patients Using Direct Oral Anticoagulants (Asian Data from the DIRECT Registry)

Abstract

For Asian patients with nonvalvular atrial fibrillation (NVAF) using direct oral anticoagulants (DOACs), performance of contemporary various bleeding risk scores in a real-world setting is unknown. The objective of this study was to externally validate the ORBIT bleeding score and the HAS-BLED score in a large pooled real-world Asian population with NVAF using DOACs. We conducted a single-center prospective observational registry of NVAF patients treated with DOACs: the DIRECT registry (UMIN000033283). We assessed predictive and discriminative performance of the ORBIT bleeding and the HAS-BLED scores for major bleeding in 2,216 patients with NVAF using DOACs (63.6% male, median age 73 years, median CHADS₂ score 2). The overall incidence of major bleeding was 4.2% after a median follow-up of 315 days (interquartile range: 76 to 621). The ORBIT bleeding and the HAS-BLED scores both had modest discrimination ability to identify those who had bled versus who had not (C index = 0.64 [95% confidence interval {CI} 0.59, 0.70] and 0.62 [95% CI 0.57, 0.68], respectively). Calibration plots of the ORBIT bleeding score showed similar predictive performance compared with the HAS-BLED score (slope: 0.91 [95% CI 0.40, 1.43] vs 0.72 [95% CI 0.03, 1.40], intercept: 0.24 [95% CI -2.13, 2.61] vs 0.71 [95% CI -2.35, 3.76], respectively). In conclusion, the ORBIT bleeding score and the HAS-BLED score in a real-world of NVAF population with DOACs showed a modest discriminative performance and a similar predictive performance for major bleeding.