Rivaroxaban vs. Warfarin in Japanese Patients With Non-Valvular Atrial Fibrillation in Relation to Age

Background: The J-ROCKET AF study found that rivaroxaban was non-inferior to warfarin with respect to the principal safety outcome in patients with atrial fibrillation (AF). The aim of this subgroup analysis was to assess the safety and efficacy of rivaroxaban and warfarin in relation to patient age. Methods and Results: A total of 39.0% were elderly (aged ≥75 years). In elderly patients, the principal safety outcome occurred at 25.05%/year with rivaroxaban vs. 16.95%/year on warfarin (hazard ratio [HR], 1.49; 95% confidence interval [CI]: 1.02–2.16), whereas the primary efficacy endpoint occurred at 2.18%/year vs. 4.25%/year (HR, 0.51; 95% CI: 0.20–1.27), respectively. There were significant interactions in the principal safety outcomes of rivaroxaban compared with warfarin between the elderly and non-elderly groups, but not in the primary efficacy endpoints (P=0.04 and 0.82 for both interactions, respectively). Furthermore, in elderly patients, in the rivaroxaban group there was a trend to increase the principal safety outcome regardless of renal function. In elderly patients with preserved renal function, however, patients on rivaroxaban had a marginally favorable trend in the primary efficacy endpoint incidence rate compared with patients on warfarin. Conclusions: There is a need to carefully consider the risks and benefits of therapy with rivaroxaban in elderly patients with non-valvular AF.  (Circ J 2014; 78: 1349–1356)