Outcomes of 10 mg Rivaroxaban in Nonvalvular Atrial Fibrillation Patients With CrCl ≥ 50 mL/min: A Retrospective Cohort Study

<b>Background:</b> The standard oral dose of rivaroxaban for nonvalvular atrial fibrillation (NVAF) patients with a creatinine clearance rate (CrCl) ≥ 50 m<i>L</i>/min is 20 mg/day in Europe and 15 mg/day in Japan. In the real world, low-dosing (10 mg/day) rivaroxaban has been widely used in clinical practice in China due to bleeding concerns. However, the impact of low-dose rivaroxaban on clinical outcomes remains uncertain. <b>Methods:</b> This retrospective study included NVAF patients with CrCl ≥ 50 mL/min treated at the Second Affiliated Hospital of Xi'an Jiaotong University from January 2017 to June 2022. Patients were divided into two groups: standard-dose (15 or 20 mg/day) and low-dose (10 mg/day). Inverse probability of treatment weighting (IPTW) was used to balance baseline characteristics. The risk of ischemic stroke (IS)+systemic embolism (SE) and bleeding was compared between the two groups by survival analysis. <b>Results:</b> A total of 1455 patients (mean age: 66.98 ± 11.16 years; 55.95% female) were included. In the low-dose group (<i>n</i> = 1176), 78 (6.63%) experienced IS/SE and 68 (5.78%) had bleeding. In the standard-dose group (<i>n</i> = 279), 13 (4.66%) experienced IS/SE and 18 (6.45%) had bleeding. Cox regression suggested that compared to the standard-dose group, patients in the low-dose group did not show a significantly different risk of IS+SE (HR = 1.01, 95% CI: 0.51-1.96, <i>p</i> = 0.999) or bleeding (HR = 0.90, 95% CI: 0.49-1.67, <i>p</i> = 0.749). Subgroup analysis revealed that for patients with BMI < 24 kg/m², low-dose rivaroxaban reduced bleeding risk (HR = 0.53, 95% CI: 0.29-0.99, <i>p</i> = 0.049). <b>Conclusion:</b> For NVAF patients with CrCl ≥ 50 mL/min in China, low-dose rivaroxaban (10 mg/day) is a viable alternative to standard doses in preventing IS/SE. In nonoverweight patients (BMI < 24 kg/m²), it offers comparable efficacy with enhanced safety.