Safety, effectiveness, and health care cost comparisons among elderly patients with venous thromboembolism prescribed warfarin or apixaban in the United States Medicare population

Curr Med Res Opin. 2019 Dec;35(12):2043-2051. doi: 10.1080/03007995.2019.1653067. Epub 2019 Sep 3.

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.

Keywords: VTE; Warfarin; apixaban; major bleeding; recurrent VTE.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Aged
  • Anticoagulants / administration & dosage
  • Anticoagulants / adverse effects
  • Female
  • Health Care Costs
  • Hemorrhage* / chemically induced
  • Hemorrhage* / diagnosis
  • Hemorrhage* / economics
  • Hospitalization* / economics
  • Hospitalization* / statistics & numerical data
  • Humans
  • Male
  • Medicare / economics
  • Pyrazoles* / administration & dosage
  • Pyrazoles* / adverse effects
  • Pyridones* / administration & dosage
  • Pyridones* / adverse effects
  • Retrospective Studies
  • Secondary Prevention / methods
  • United States / epidemiology
  • Venous Thromboembolism* / drug therapy
  • Venous Thromboembolism* / economics
  • Venous Thromboembolism* / epidemiology
  • Warfarin* / administration & dosage
  • Warfarin* / adverse effects

Substances

  • Anticoagulants
  • Pyrazoles
  • Pyridones
  • apixaban
  • Warfarin