title: Cost-effectiveness Analysis of Apixaban against Warfarin for Stroke Prevention in Patients with Nonvalvular Atrial Fibrillation in Japan.
abstract: OBJECTIVE
  The aim of this study was to evaluate the cost-effectiveness of apixaban compared with to warfarin, current standard of care, for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF) in Japan.
  
  
  METHODS
  A previously published lifetime Markov model was adapted to evaluate the cost-effectiveness of apixaban compared with warfarin in patients with NVAF in Japan. In the same model, the costs associated with each clinical event and background mortality were replaced with Japanese data. Whenever available, some of the utility parameters were derived from Japanese published literature. Lifetime horizon was selected to evaluate the value of the treatment benefit (stroke prevention) against potential risks (such as major bleedings) among patients with NVAF. Direct medical cost, long-term care cost, and quality-adjusted life years (QALYs) were calculated from the payers' perspective.
  
  
  RESULTS
  Compared with warfarin, treatment with apixaban was estimated to increase life expectancy by 0.231 year or 0.240 QALYs while treatment cost increased by ¥511,692 (US $5117 at an exchange rate of US $1 = ¥100). The incremental cost-effectiveness ratio was ¥2,135,743 per QALY (US $21,357 per QALY). On the basis of the results of the probabilistic sensitivity analysis, when the willingness-to-pay threshold was set at approximately ≥¥2,250,000 (US $22,500) per QALY, the probability of apixaban being cost-effective was ≥50%. Assuming a willingness-to-pay threshold of ¥5,000,000 (US $50,000) and ¥6,700,000 (US $67,000) in Japan, the probability of apixaban being cost-effective was 85% and 91%, respectively.
  
  
  CONCLUSIONS
  Although most participants in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial used for the efficacy data of apixaban in the model were non-Japanese patients, the impact of the limitations on our results was considered small, and our results were deemed robust because of the additional effect in Japanese patients compared with that in the global population according to the subanalysis of Japanese patients in the trial. Therefore, based on an adaptation of a published Markov model, apixaban is a cost-effective alternative to warfarin in Japan for stroke prevention among patients with NVAF.
authors.affiliation: The University of Tokyo, Tokyo, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Kamae
authors.affiliation: Kumamoto City Hospital, Kumamoto, Japan.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Hashimoto
authors.affiliation: National Hospital Organization, Osaka National Hospital, Osaka, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Koretsune
authors.affiliation: Saitama International Medical Center, Saitama, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Tanahashi
authors.affiliation: Crecon Medical Assessment Inc, Tokyo, Japan. Electronic address: tatsunori.murata@crecon.jp.
authors.forename: Tatsunori
authors.initials: T
authors.lastname: Murata
authors.affiliation: US Health Economics and Outcomes Research, EMD Serono, Rockland, MA.
authors.forename: Hemant
authors.initials: H
authors.lastname: Phatak
authors.affiliation: Global Health Economics and Outcomes Research and Evidence, Pfizer Inc, and Weill Medical College of Cornell University, New York, New York, USA.
authors.forename: Larry Z
authors.initials: LZ
authors.lastname: Liu
authors.affiliation: Health Economics and Outcomes Research, Bristol-Myers K.K., Tokyo, Japan.
authors.forename: Ann C
authors.initials: AC
authors.lastname: Tang
authors.affiliation: Worldwide Health Economics and Outcomes Research, Bristol-Myers Squibb, Princeton, New Jersey.
authors.forename: Peter
authors.initials: P
authors.lastname: Feng Wang
authors.affiliation: Hirosaki University Graduate School of Medicine, Aomori, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Okumura
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000191:economics / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000453:epidemiology*; D003362:Cost-Benefit Analysis; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D011720:Pyrazoles / Q000191:economics / Q000627:therapeutic use; D011728:Pyridones / Q000191:economics / Q000627:therapeutic use; D020521:Stroke / Q000188:drug therapy / Q000191:economics / Q000453:epidemiology / Q000517:prevention & control; D014859:Warfarin / Q000191:economics / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D011720:Pyrazoles; D011728:Pyridones; C522181:apixaban; D014859:Warfarin
keywords: Japan; apixaban; cost-effectiveness; nonvalvular atrial fibrillation