title: A population-based nested case-control study of the costs of hip and knee replacement surgery.
abstract: BACKGROUND
  Studies of total joint arthroplasty (TJA) have not evaluated the costs and outcomes in the context of expected arthritis worsening.
  
  
  OBJECTIVE
  Using a cost-consequence approach, to examine changes in direct health care costs and arthritis severity after TJA for hip/knee arthritis compared with contemporaneous changes in matched controls.
  
  
  METHODS
  Case control study nested in a population-based prospective cohort.
  
  
  METHODS
  In a population cohort with disabling hip/knee osteoarthritis followed from 1996 to 2003, primary TJA recipients were matched with cohort nonrecipients on age, sex, region of residence, comorbidity, and inflammatory arthritis diagnosis.
  
  
  METHODS
  Pre- and postoperative total and arthritis-attributable direct health care costs, arthritis severity, and general health status were compared for cases and matched controls.
  
  
  RESULTS
  Of 2109 participants with no prebaseline TJA, 185 cases received a single elective TJA during the follow-up period; of these, 183 cases and controls were successfully matched. Mean age was 71 years, 77.6% were female, 35.5% had > or =2 comorbidities, and 81.5% had > or =2 joints affected. At baseline, controls had less pain and disability and lower total and arthritis-attributable health care costs than cases. After surgery, although overall health care utilization was unchanged, cases experienced significant decreases in arthritis-attributable costs (mean decrease $278 including prescription drugs) and pain and disability (P < 0.0001 for all). Over the same time period, controls experienced a significant increase in total health care costs (mean increase $1978 including prescription drugs, P = 0.04) and no change or worsening of their arthritis status.
  
  
  CONCLUSIONS
  Compared with matched controls, arthroplasty is associated with significant reductions in pain, disability, and arthritis-attributable direct costs.
authors.affiliation: Department of Medicine, Women's College Hospital, 76 Grenville Street, Toronto, Ontario, Canada. gillian.hawker@wchospital.ca
authors.forename: Gillian A
authors.initials: GA
authors.lastname: Hawker
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Badley
authors.forename: Ruth
authors.initials: R
authors.lastname: Croxford
authors.forename: Peter C
authors.initials: PC
authors.lastname: Coyte
authors.forename: Richard H
authors.initials: RH
authors.lastname: Glazier
authors.forename: Jun
authors.initials: J
authors.lastname: Guan
authors.forename: Bart J
authors.initials: BJ
authors.lastname: Harvey
authors.forename: J I
authors.initials: JI
authors.lastname: Williams
authors.forename: James G
authors.initials: JG
authors.lastname: Wright
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000191:economics*; D019645:Arthroplasty, Replacement, Knee / Q000191:economics*; D016022:Case-Control Studies; D018672:Community Health Planning; D017281:Cost of Illness; D003362:Cost-Benefit Analysis; D006233:Persons with Disabilities / Q000534:rehabilitation / Q000706:statistics & numerical data; D005260:Female; D017048:Health Care Costs / Q000706:statistics & numerical data*; D006302:Health Services Research; D006304:Health Status; D006801:Humans; D008297:Male; D009313:National Health Programs / Q000191:economics / Q000706:statistics & numerical data; D009864:Ontario / Q000453:epidemiology; D015207:Osteoarthritis, Hip / Q000150:complications / Q000191:economics / Q000453:epidemiology / Q000601:surgery; D020370:Osteoarthritis, Knee / Q000150:complications / Q000191:economics / Q000453:epidemiology / Q000601:surgery; D010146:Pain / Q000209:etiology / Q000517:prevention & control; D011446:Prospective Studies; D016896:Treatment Outcome