title: Development and preliminary evaluation of the OsteoArthritis Questionnaire (OA-Quest): a psychometric study.
abstract: This study reports the development of the OsteoArthritis Questionnaire (OA-Quest) - a new measure designed to comprehensively capture the potentially modifiable burden of osteoarthritis.
  
  
  
  Item development was guided by the a priori conceptual framework of the Personal Burden of Osteoarthritis (PBO) which captures 8 dimensions of osteoarthritis burden (Physical distress, Fatigue, Physical limitations, Psychosocial distress, Physical de-conditioning, Financial hardship, Sleep disturbances, Lost productivity). One hundred and twenty three candidate items were pretested in a clinical sample of 18 osteoarthritis patients. The measurement properties of the OA-Quest were assessed with exploratory factor analysis (EFA), Rasch modelling, and confirmatory factor analysis (CFA) in a community-based sample (n = 792).
  
  
  
  EFA replicated 7 of the 8 PBO domains. An exception was PBO Fatigue domain, with items merging into the Physical distress subscale in the OA-Quest. Following item analysis, a 42-item 7-subscale questionnaire was constructed, measuring Physical distress (seven items, Cronbach's α = 0.93), Physical limitations (11 items, α = 0.95), Psychosocial distress (seven items, α = 0.93), Physical de-conditioning (four items, α = 0.87), Financial hardship (four items, α = 0.93), Sleep disturbances (five items, α = 0.96), and Lost productivity (four items α = 0.90). A highly restricted 7-factor CFA model had excellent fit with the data (χ(2)(113) = 316.36, P < 0.001; chi-square/degrees of freedom = 2.8; comparative fit index [CFI] = 0.97; root mean square error of approximation [RMSEA] = 0.07), supporting construct validity of the new measure.
  
  
  
  The OA-Quest is a new measure of osteoarthritis burden that is founded on a comprehensive conceptual model. It has strong evidence of construct validity and provides reliable measurement across a broad range of osteoarthritis burden.
authors.affiliation: Institute for Health and Ageing, Australian Catholic University, Level 6, 215 Spring Street, Melbourne 3000, Victoria, Australia. Electronic address: Lucy.Busija@acu.edu.au.
authors.forename: L
authors.initials: L
authors.lastname: Busija
authors.affiliation: Monash Department of Clinical Epidemiology, Cabrini Hospital and Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Suite 41 Cabrini Medical Centre, 183 Wattletree Road, Malvern 3144, Victoria, Australia. Electronic address: Rachelle.Buchbinder@monash.edu.
authors.forename: R
authors.initials: R
authors.lastname: Buchbinder
authors.affiliation: Public Health Innovation, Population Health Strategic Research Centre, School of Health and Social Development, Faculty of Health, Deakin University, 221 Burwood Highway, Burwood 3125, Victoria, Australia. Electronic address: Richard.Osborne@deakin.edu.au.
authors.forename: R H
authors.initials: RH
authors.lastname: Osborne
mesh_terms: D004526:Efficiency; D005163:Factor Analysis, Statistical; D006801:Humans; D010003:Osteoarthritis; D011594:Psychometrics; D011795:Surveys and Questionnaires
keywords: Confirmatory factor analysis; Exploratory factor analysis; Osteoarthritis; Patient-reported outcome measures; Rasch modelling