title: Prevalence of total knee arthroplasty and its predictive factors in Japanese patients with rheumatoid arthritis: Analysis using the NinJa cohort.
abstract: OBJECTIVE
  The aim of this study was to clarify the prevalence and the predictive factors for undergoing total knee arthroplasty (TKA) among patients with rheumatoid arthritis (RA).
  
  
  METHODS
  The data of 1,134 patients with RA who were enrolled in the Japanese nationwide cohort database NinJa in 2003 and consecutively followed up until 2009 were analyzed.
  
  
  RESULTS
  Seventy-six patients underwent TKA during the observation period. The yearly progression of the modified Health Assessment Questionnaire or mHAQ score from 2003 to 2004, but not the yearly progression of the Disease Activity Score in 28 Joints or DAS28 or patient visual analog scale (VAS) score, was significantly higher in the patients who underwent TKA than those who did not. Multivariate analysis showed that knee involvement in the disease, high Steinbrocker stage (III or IV), and high patient VAS score at the time of enrollment were powerful predictive factors, with hazard ratios of 4.01, 3.71, and 1.20, respectively. According to survival analysis with TKA as an endpoint, patients with knee involvement in the disease at the time of enrollment had a significantly worse 5-year survival rate than did those without knee involvement (83.5% vs. 97.0%, respectively).
  
  
  CONCLUSIONS
  Several factors were elucidated as predictive factors for undergoing TKA among patients with RA.
authors.affiliation: a Department of Orthopaedic Surgery , Faculty of Medicine, The University of Tokyo , Tokyo , Japan.|b Department of Orthopaedic Surgery , Teikyo University Mizonokuchi Hospital , Kanagawa , Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Yasui
authors.affiliation: a Department of Orthopaedic Surgery , Faculty of Medicine, The University of Tokyo , Tokyo , Japan.
authors.forename: Jinju
authors.initials: J
authors.lastname: Nishino
authors.affiliation: a Department of Orthopaedic Surgery , Faculty of Medicine, The University of Tokyo , Tokyo , Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Shoda
authors.affiliation: a Department of Orthopaedic Surgery , Faculty of Medicine, The University of Tokyo , Tokyo , Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Koizumi
authors.affiliation: a Department of Orthopaedic Surgery , Faculty of Medicine, The University of Tokyo , Tokyo , Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Ohashi
authors.affiliation: a Department of Orthopaedic Surgery , Faculty of Medicine, The University of Tokyo , Tokyo , Japan.
authors.forename: Yuho
authors.initials: Y
authors.lastname: Kadono
authors.affiliation: a Department of Orthopaedic Surgery , Faculty of Medicine, The University of Tokyo , Tokyo , Japan.
authors.forename: Sakae
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: c Clinical Research Center for Allergy and Rheumatology, Sagamihara National Hospital, National Hospital Organization , Kanagawa , Japan.
authors.forename: Shigeto
authors.initials: S
authors.lastname: Tohma
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000175:diagnosis / Q000601:surgery*; D019645:Arthroplasty, Replacement, Knee; D016208:Databases, Factual; D018450:Disease Progression; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012720:Severity of Illness Index
keywords: Database analysis; Predictive factors; Rheumatoid arthritis; Total knee arthroplasty