Effectiveness and Safety of Different Rivaroxaban Dosage Regimens in Patients with Non-Valvular Atrial Fibrillation: A Nationwide, Population-Based Cohort Study

The objective of this study is to evaluate the effectiveness of different rivaroxaban dosage regimens in preventing ischemic stroke and systemic thromboembolism among Asians. A retrospective cohort study was conducted on data from nationwide insurance claims in Taiwan. Patients with non-valvular atrial fibrillation under warfarin or rivaroxaban therapy were included. Propensity score matching was used to balance the covariates, and Cox-proportional hazard models were applied to compare the effectiveness and safety of each treatment group. Rivaroxaban was associated with a significantly lower risk of venous thromboembolism (hazard ratio [HR]: 0.51; 95% confidence interval [CI]: 0.29–0.92, P = 0.02) and intracranial hemorrhage (HR: 0.48; 95% CI: 0.32–0.72, P < 0.001) than warfarin. Rivaroxaban 20 mg and 15 mg were associated with a significantly lower risk of ischemic stroke (20 mg, HR: 0.48; CI: 0.29–0.80, P = 0.005; 15 mg, HR: 0.69; CI: 0.53–0.90, P = 0.005), but rivaroxaban 10 mg was not. In the subgroup analysis of patients older than 65 years, the results were generally the same, except that rivaroxaban had a significantly lower risk of ischemic stroke than warfarin.