WASHINGTON, DC—While previous studies have shown that direct oral anticoagulants have been associated with similar or lower rates of major bleeding compared to warfarin, few studies have evaluated the costs associated with major bleeding. In a study presented at the ACC.17 Scientific Session, Alpesh Amin and coauthors aimed to compare the risk and associated costs of major bleeding in oral anticoagulant-naïve patients with non-valvular atrial fibrillation (NVAF).

The researchers searched the U.S. Medicare database for NVAF patients 65 years of age and older who were newly prescribed one of the following medications: apixaban (n=20,853), dabigatran (n=16,743), rivaroxaban (n=53,146), or warfarin (n=95,390); patients with valvular heart disease, transient atrial fibrillation, venous thromboembolism, or valve replacement/surgery were excluded. They used ICD9 codes from hospitalization claims to identify major bleeding; medical costs for major bleeding were calculated per patient/month (PPPM). 

To balance demographics and other clinical factors, 1:1 propensity score matching was used (20,803 apixaban-warfarin matched pairs, 16,731 warfarin-dabigatran matched pairs, 52,476 warfarin-rivaroxaban matched pairs); hazard ratio (HR) was estimated using Cox proportional hazards models.

Compared to warfarin, apixaban and dabigatran initiators had a significantly lower risk of major bleeding (HR: 0.51 and 0.79, respectively) with lower associated costs (apixaban: $286 vs. warfarin: $537; dabigatran: $367 vs. warfarin: $452). While risk of major bleeding was higher with rivaroxaban (HR: 1.17), the costs associated were similar compared to warfarin ($524 vs. $500).

“In the US Medicare population, NVAF patients prescribed apixaban and dabigatran had significantly lower risk of major bleeding and major bleeding-related medical costs compared to those prescribed warfarin,” concluded the authors.