A post-marketing assessment of major bleeding in total hip and total knee replacement surgery patients receiving rivaroxaban

BACKGROUND: Rivaroxaban is a novel oral anticoagulant indicated for prophylaxis against deep vein thrombosis and pulmonary embolism in patients undergoing total hip replacement (THR) or total knee replacement (TKR) surgery. OBJECTIVE: To evaluate major bleeding (MB) in THR/TKR patients receiving post-operative rivaroxaban. METHODS: Electronic medical records of nearly 10 million US Department of Defense (DoD) beneficiaries were queried from 1 January 2013 through 30 June 2015. Using the validated Cunningham case-finding algorithm, post-surgical MB events in rivaroxaban users were identified and analyzed. The incidence of MB was determined, and descriptive statistics were used to compare patient characteristics and other covariates in those with and without MB. Two additional methods were used to explore and identify bleeding cases that were not considered MB events per the study case-finding algorithm. RESULTS: A total of 12,429 patients received THR and/or TKR surgery, and were post-operatively prescribed rivaroxaban. Nine patients had MB, yielding an incidence proportion of 0.07% (95% CI 0.02-0.13). The alternative case-finding methods found bleeding incidences of 0.46% and 0.21%, though it is not clear whether these are clinical MB cases, since the alternative methods were not validated. CONCLUSIONS: The incidence of MB in this retrospective analysis is lower than that observed in the clinical trials of rivaroxaban. Whether this is due to lower real-world MB rates or challenges with case-finding algorithms is unclear.