Comparison of effectiveness and safety of warfarin with rivaroxaban in patients with atrial fibrillation: a multicenter retrospective cohort study in Addis Ababa, Ethiopia

Background The risk of thromboembolic stroke increases fivefold in patients with atrial fibrillation (AF). Several real-world comparative studies have examined the clinical outcomes of warfarin and rivaroxaban in patients with AF. There are limited data on the clinical outcomes of patients receiving warfarin or rivaroxaban in Ethiopia. This study aimed to compare the effectiveness and safety of warfarin with rivaroxaban in patients with atrial fibrillation. Methods A two-year multicenter retrospective cohort study was conducted, including adult patients with atrial fibrillation treated with rivaroxaban or warfarin at three hospitals in Addis Ababa between April 1, 2022, and March 31, 2024. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) software version 28. The chi-square and independent samples t-tests were used to analyze categorical and continuous variables, respectively. A multivariable Cox proportional hazards model was used to estimate the hazard ratios for developing the outcomes. Kaplan-Meier survival curves were drawn to show the percentage of patients in both groups who did not experience the outcomes during the study period. Statistical significance was set at p < 0.05. Results Among 290 patients with AF, 151 (52.1%) were female, with a mean age of 68.90 (± 9.52) years. The composite outcomes of ischemic stroke (HR, 0.264; 95% CI, 0.116–0.603; p = 0.002) and hemorrhagic stroke (HR, 0.112; 95% CI, 0.034–0.367; p < 0.001) were significantly lower in the rivaroxaban group than in the warfarin group. Regarding safety, warfarin use was associated with a significantly higher rate of gastrointestinal bleeding than rivaroxaban (HR, 0.409; 95% CI: 0.199–0.844; p = 0.016). Kaplan–Meier survival analysis with the log-rank test demonstrated significantly lower incidences of ischemic stroke ( p = 0.011), hemorrhagic stroke ( p = 0.001), and gastrointestinal bleeding ( p = 0.003) in the rivaroxaban group than in the warfarin group. Conclusions The composite outcomes of ischemic stroke, hemorrhagic stroke, and gastrointestinal bleeding were significantly lower in the rivaroxaban group, indicating its better effectiveness and safety. These findings suggest that rivaroxaban may be a safer and more effective alternative to warfarin for long-term anticoagulation therapy.