Comparative effectiveness, safety, and costs of rivaroxaban and warfarin among morbidly obese patients with atrial fibrillation

BACKGROUND: or body weight >120 kg). METHODS: Using data from 2 US healthcare claims databases, we identified patients initiating rivaroxaban or warfarin who had ≥1 medical claim with an AF diagnosis, a diagnostic code for morbid obesity (ICD-9: 278. 01, V85. 4%; ICD-10: E66. 01%, E66. 2%, Z68. 4%), and a minimum continuous enrollment of 12 months before and 3 months after treatment initiation. Patients were excluded if they had mitral stenosis, a mechanical heart valve procedure, an organ/tissue transplant, or an oral anticoagulant prescription prior to the index date. Rivaroxaban and warfarin patients were 1: 1 propensity score matched. Conditional logistic regression was used to compare ischemic stroke/systemic embolism and major bleeding risk. Generalized linear models were used to compare healthcare resource utilization and costs. RESULTS: A total of 3563 matched pairs of morbidly obese AF patients treated with rivaroxaban or warfarin were identified. The majority (81. 4%) of patients in the rivaroxaban cohort were receiving the 20 mg dose. The rivaroxaban and warfarin cohorts were well balanced after propensity score matching. The risks of ischemic stroke/systemic embolism and major bleeding were similar for rivaroxaban and warfarin users (stroke/systemic embolism: 1. 5% vs 1. 7%; odds ratio OR: 0. 88; 95% confidence interval CI: 0. 60, 1. 28; P =. 5028; major bleeding: 2. 2% vs 2. 7%; OR: 0. 80; 95% CI: 0. 59, 1. 08; P =. 1447). Total healthcare costs including medication costs per patient per year (PPPY) were significantly lower with rivaroxaban versus warfarin (48, 552 vs 52, 418; P =. 0025), which was primarily driven by lower hospitalization rate (50. 2% vs 54. 1%; P =. 0008), shorter length of stay (7. 5 vs 9. 1 days; P =. 0010), and less outpatient service utilization (86 vs 115 visits PPPY; P <. 0001). CONCLUSIONS: Morbidly obese AF patients treated with rivaroxaban had comparable risk of ischemic stroke/systemic embolism and major bleeding as those treated with warfarin, but lower healthcare resource utilization and costs.