Comparison of the CHA₂DS₂-VASc, CHADS₂, HAS-BLED, ORBIT, and ATRIA Risk Scores in Predicting Non-Vitamin K Antagonist Oral Anticoagulants-Associated Bleeding in Patients With Atrial Fibrillation

The increasing adoption of non-vitamin K antagonist oral anticoagulants (NOACs) for stroke prevention in atrial fibrillation (AF) necessitates a reassessment of bleeding risk scores. Because known risk factors for bleeding are largely the same as for stroke, we hypothesize that stroke risk scores could also be used to identify patients with high bleeding risks. We aimed to compare the performance of 2 stroke risk scores (Congestive Heart failure, hypertension, Age ≥75 [doubled], Diabetes, Stroke [doubled], Vascular disease, Age 65-74, and Sex [female] [CHA₂DS₂-VASc] and Cardiac failure, Hypertension, Age, Diabetes, Stroke [Doubled] [CHADS₂]) and 3 bleeding risk scores (hypertension, abnormal renal/liver function [1 point each], stroke, bleeding history or predisposition, labile INR, elderly [.65 years], drugs/alcohol concomitantly [1 point each] [HAS-BLED], Outcomes Registry for Better Informed Treatment of Atrial Fibrillation [ORBIT], and AnTicoagulation and Risk factors In Atrial fibrillation [ATRIA]) in predicting major and intracranial bleeding. Using a large US commercial insurance database, we identified 39,539 patients with nonvalvular AF who started NOACs between October 1, 2010 and June 30, 2015. The performance of risk scores was compared using C-statistic and net reclassification improvement (NRI). Over a total of 22,583 person-years, 665 patients (2.94% per year) had major bleeding, including 74 intracranial hemorrhages (0.33% per year). For the prediction of major bleeding, CHA₂DS₂-VASc had the highest C-statistic both as a continuous score (C-statistic 0.68) and as a categorical score (C-statistic 0.65). For the prediction of intracranial bleeding, CHADS₂ had the highest C-statistic both as a continuous score (C-statistic 0.66) and as a categorical score (C-statistic 0.66). There were no statistically significant differences between scores based on NRI. In conclusion, CHA₂DS₂-VASc, CHADS₂, HAS-BLED, ORBIT, and ATRIA had similar, albeit modest, performance in predicting NOAC-associated bleeding in patients with AF. Careful assessment and active management of bleeding risk factors may be warranted in all patients on NOACs who have high stroke risk scores.