CHA2DS2-VASc Scores and Major Bleeding in Patients With Nonvalvular Atrial Fibrillation Who Are Receiving Rivaroxaban

Abstract

Study objective: Assessing stroke risk associated with nonvalvular atrial fibrillation depends on the evaluation of patient characteristics and clinical features. Clinicians must determine that the net clinical benefit from anticoagulation therapy outweighs its risk, namely, bleeding. Risk assessment for stroke is commonly performed by calculating a CHA₂DS₂-VASc (congestive heart failure/left ventricular dysfunction, hypertension, ≥75 years, diabetes mellitus, previous stroke or transient ischemic attack or thromboembolism, vascular disease, aged 65 to 74 years, sex female) score. It is possible that CHA₂DS₂-VASc scores also have a relationship with the incidence of major bleeding. We examined the relationship between CHA₂DS₂-VASc scores and major bleeding in rivaroxaban users with nonvalvular atrial fibrillation.

Methods: Electronic medical records of more than 10 million patients from the Department of Defense Military Health System were queried to identify patients with nonvalvular atrial fibrillation who received rivaroxaban from January 1, 2013, to June 30, 2015. Baseline characteristics of the study population were described by CHA₂DS₂-VASc scores and major bleeding status; major bleeding incidence was evaluated by CHA₂DS₂-VASc score category and for each CHA₂DS₂-VASc component.

Results: Overall, 44,793 patients met the inclusion criteria for this analysis. The major bleeding incidence rate was 2.84 (95% confidence interval 2.69 to 3.00) per 100 person-years. The incidence of major bleeding increased from 0.30 to 5.40 per 100 person-years among patients with a CHA₂DS₂-VASc score of 0 to 5 or higher, respectively. Fatal outcomes among patients with major bleeding were positively correlated with CHA₂DS₂-VASc scores; patients with higher scores had higher mortality rates. The CHA₂DS₂-VASc component with the highest major bleeding incidence was for vascular disease, 5.69 (95% confidence interval 5.18 to 6.24) per 100 person-years.

Conclusion: Higher CHA₂DS₂-VASc scores are associated with increased incidence of major bleeding in nonvalvular atrial fibrillation patients receiving rivaroxaban.