title: Risk factors for early revision after primary total hip arthroplasty in Medicare patients.
abstract: BACKGROUND
  Patient, surgeon, health system, and device factors are all known to influence outcomes in THA. However, patient-related factors associated with an increased risk of early failure are poorly understood, particularly in elderly patients.
  
  
  OBJECTIVE
  We identified specific demographic and clinical characteristics associated with increased risk of early revision in Medicare patients with THA.
  
  
  METHODS
  The Medicare 5% national sample administrative database was used to calculate the relative risk of revision within 12 months following primary THA as a function of baseline medical comorbidities in 56,030 Medicare patients who underwent primary THA between 1998 and 2010. The impact of 29 comorbid conditions on risk of early revision was examined using Cox regression, controlling for age, sex, race, US Census region, socioeconomic status, and all other baseline comorbidities.
  
  
  RESULTS
  Depression, rheumatologic disease, psychoses, renal disease, chronic urinary tract infection, and congestive heart failure were associated with revision THA within 12 months of the index arthroplasty (p ≤ 0.038 for all comparisons; risk factors listed in order of significance).
  
  
  CONCLUSIONS
  This information is important when counseling elderly patients with THA regarding the risk of early failure and for risk stratifying publicly reported outcomes in Medicare patients with THA.
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Francisco, 500 Parnassus Avenue, MU 320 W, San Francisco, CA, 94143-0728, USA, kevin.bozic@ucsf.edu.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Bozic
authors.forename: Edmund
authors.initials: E
authors.lastname: Lau
authors.forename: Kevin
authors.initials: K
authors.lastname: Ong
authors.forename: Vanessa
authors.initials: V
authors.lastname: Chan
authors.forename: Steven
authors.initials: S
authors.lastname: Kurtz
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Vail
authors.forename: Harry E
authors.initials: HE
authors.lastname: Rubash
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Berry
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D015897:Comorbidity; D005260:Female; D006621:Hip Joint / Q000601:surgery*; D006801:Humans; D008297:Male; D006278:Medicare; D016017:Odds Ratio; D018579:Patient Selection; D011183:Postoperative Complications / Q000601:surgery*; D016016:Proportional Hazards Models; D012086:Reoperation; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D012959:Socioeconomic Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States