The impact of factor Xa inhibitors on bleeding risk in patients with respiratory diseases

It is unclear which factor Xa (FXa) inhibitors are associated with higher bleeding risk in patients with respiratory diseases, and there are no studies on the association between prothrombin time–international normalized ratio (PT–INR) and bleeding risk. We conducted a retrospective cohort study comparing 1-year-outcomes and PT–INR between patients with respiratory diseases treated with rivaroxaban (R group, n = 82) or edoxaban (E group, n = 138) for atrial fibrillation or venous thromboembolism from 2013 to 2021. The most frequent event of all bleeding discontinuations was respiratory bleeding in both groups (7.3 and 4.3%, respectively). The cumulative incidence of bleeding discontinuation was significantly higher in the R group (25.6%) than in the E group (14.4%) (hazard ratio [HR], 2.29; 95% confidence interval [CI] 1.13–4.64; P = 0.023). PT–INR after initiation of therapy significantly increased and was higher in the R group than in the E group (median value, 1.4 and 1.2, respectively; P < 0.001). Multivariate analysis using Cox proportional hazards and Fine-Gray models revealed that PT–INR after initiation of therapy was an independent risk factor of bleeding discontinuation events (HR = 4.37, 95% CI 2.57–7.41: P < 0.001). Respiratory bleeding occasionally occurs in patients receiving FXa inhibitors, and monitoring the PT–INR may need to ensure safety.