title: Responsiveness of health state utility values in knee osteoarthritis.
abstract: OBJECTIVE
  Adaptive tests are increasingly being used to assess health-related quality of life in patients with a variety of medical conditions, including osteoarthritis (OA) of the knee. This approach has recently been used to assess health state utility valuations (HSUV) for use in quality-adjusted life-year calculations. To accurately assess incremental value for money, these tools must be responsive. Therefore, we examined the responsiveness of the Health Utilities Index mark 3 (HUI3) and Paper Adaptive Test-5D (PAT-5DQOL) in a group of patients with knee OA.
  
  
  METHODS
  We used patient-level data from a randomized controlled trial evaluating a pharmacist-initiated multidisciplinary intervention in newly diagnosed patients with knee OA. The mean change for utility scores from baseline to 6 months was calculated, as well as effect size (ES) and standardized response mean (SRM) for the HUI3 and PAT-5DQOL, and generalized additive model plots, using the Western Ontario and McMaster Osteoarthritis index as a reference standard.
  
  
  RESULTS
  When patients were assessed based on whether their condition had improved, remained unchanged, or worsened over time, the PAT-5DQOL showed greater responsiveness in patients whose condition had either improved or worsened. ES and SRM were generally small for both instruments.
  
  
  CONCLUSIONS
  The PAT-5DQOL is more responsive to change over time than the HUI3 in patients with knee OA.
authors.affiliation: From the School of Pharmacy, Memorial University, St. John's, Newfoundland and Labrador; Collaboration for Outcomes Research and Evaluation (CORE), and School of Population and Public Health, University of British Columbia, Arthritis Research Centre, and Centre for Health Evaluation and Outcome Sciences, Providence Health Care Research Institute, Vancouver, British Columbia, Canada.
authors.forename: Erin M
authors.initials: EM
authors.lastname: Davis
authors.forename: Larry D
authors.initials: LD
authors.lastname: Lynd
authors.forename: Maja
authors.initials: M
authors.lastname: Grubisic
authors.forename: Jacek A
authors.initials: JA
authors.lastname: Kopec
authors.forename: Eric C
authors.initials: EC
authors.lastname: Sayre
authors.forename: Jolanda
authors.initials: J
authors.lastname: Cibere
authors.forename: John
authors.initials: J
authors.lastname: Esdaile
authors.forename: Carlo A
authors.initials: CA
authors.lastname: Marra
mesh_terms: D000368:Aged; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D020370:Osteoarthritis, Knee / Q000453:epidemiology* / Q000503:physiopathology* / Q000628:therapy; D010147:Pain Measurement; D011788:Quality of Life; D019057:Quality-Adjusted Life Years; D012720:Severity of Illness Index; D016896:Treatment Outcome
keywords: ADAPTIVE TESTS; HEALTH CARE EVALUATION MECHANISMS; HEALTH-RELATED QUALITY OF LIFE; KNEE OSTEOARTHRITIS; QUALITY-ADJUSTED LIFE-YEARS