Safety, effectiveness, and health care cost comparisons among elderly patients with venous thromboembolism prescribed warfarin or apixaban in the United States Medicare population. (2nd December 2019)

• Record Type: Journal Article
• Authors: Hlavacek, Patrick; Guo, Jennifer D.; Rosenblatt, Lisa; Keshishian, Allison; Russ, Cristina; Mardekian, Jack; Ferri, Mauricio; Poretta, Tayla; Yuce, Huseyin; McBane, Robert
• Is Part Of: Current medical research and opinion. Volume 35:Number 12(2019)
• Page Start: 2043
• Page End: 2051
• Publication Date: 2019-12-02
• Subjects: Warfarin -- apixaban -- recurrent VTE -- major bleeding -- VTE; Clinical medicine -- Periodicals; Therapeutics -- Periodicals; 615.5
• DOI: 10.1080/03007995.2019.1653067
• Languages: English
• ISSNs: 0300-7995

Abstract

Abstract: Objective: To compare safety, effectiveness, and healthcare costs of major bleeding (MB), clinically relevant non-major (CRNM) bleeding, recurrent venous thromboembolism (VTE), and all-cause hospitalization among elderly Medicare VTE patients prescribed warfarin vs apixaban. Methods: Using 100% Medicare data, elderly patients prescribed apixaban or warfarin within 30 days after a VTE encounter were identified. Patients had continuous health plan enrollment and no parenteral or oral anticoagulant use ≤6 months preceding the VTE encounter. Cohorts were balanced using 1:1 propensity score matching (PSM). Cox proportional hazard models were used to assess the risk of MB, CRNM bleeding, recurrent VTE, and all-cause hospitalization. Generalized linear and two-part models were used to estimate MB-, recurrent VTE-, and all-cause related costs (per patient per month [PPPM]). Results: In the pre-matched cohort, 25, 284 (66.9%) patients were prescribed warfarin and 12, 515 (33.1%) apixaban. After 1:1 PSM, 11, 363 matched pairs of apixaban-warfarin patients were included for a mean follow-up of 4.0 and 4.4 months, respectively. Matched cohorts had a mean age of 78 years and mean Charlson Comorbidity Index score of 2.9. Warfarin was associated with a higher risk of MB (hazard ratio [HR] = 1.31; 95% confidence interval [CI] = 1.10–1.57) and CRNM bleeding (HR = 1.31; 95% CI = 1.19–1.43) vs apixaban. The risks of recurrent VTE (HR = 0.96; 95% CI = 0.70–1.33) and all-cause hospitalization (HR = 1.05; 95% CI = 0.99–1.12) were similar among warfarin and apixaban patients. Warfarin patients had higher MB-related ($147 vs $75; p = .003) and all-cause costs PPPM ($3, 267 vs $3, 033; p < .001), but similar recurrent VTE-related medical costs PPPM ($30 vs $36; p = .516) vs apixaban patients. Conclusions: Warfarin was associated with significantly higher risk of MB and CRNM bleeding as well as higher MB-related and all-cause costs vs apixaban patients. Recurrent VTE risk and costs were similar among warfarin and apixaban patients.