title: Psychometric properties of the OARSI/OMERACT osteoarthritis pain and functional impairment scales: ICOAP, KOOS-PS and HOOS-PS.
abstract: OBJECTIVE
  To evaluate the psychometric properties of the OARSI-OMERACT questionnaires in comparison to the existing validated scales.
  
  
  METHODS
  Consecutive hip or knee osteoarthritis patients consulting in an orthopedic department were enrolled in the study. Data collected were pain using the Intermittent and Constant Osteoarthritis Pain (ICOAP), a Numeric Rating Scale (NRS), the Western Ontario McMaster Universities' Osteoarthritis Index (WOMAC) pain subscale, the Lequesne pain subscale; functional impairment using the Knee disability and Osteoarthritis Outcome Score-Physical Function Shortform (KOOS-PS), the Hip disability and Osteoarthritis Outcome Score-Physical Function Shortform (HOOS-PS), a NRS, the WOMAC function sub-scale, the Lequesne function subscale. Validity was assessed by calculating the Spearman's correlation coefficient between all the scales. Reliability was assessed in out-patients with stable disease comparing the data collected within 2 weeks using the intra-class correlation coefficient (ICC). Responsiveness was assessed on the data from hospitalised patients prior to and 12 weeks after a total joint replacement (TJR) using the standardised response mean.
  
  
  RESULTS
  Three hundred patients (mean age=68 years, females=62%, hip OA=57%) were included. There was a moderate to good correlation between ICOAP, KOOS-PS, HOOS-PS and the WOMAC, NRS and Lequesne scales. Reliability of the ICOAP hip OA HOOS-PS and KOOS-PS was good (ICC range 0.80-0.81) whereas it was moderate for knee ICOAP (ICC=0.65). Responsiveness of the ICOAP, KOOS-PS and HOOS-PS 12 weeks after TJR was comparable to responsiveness of other scales (SRM range: 0.54-1.82).
  
  
  CONCLUSIONS
  The psychometric properties of the ICOAP, KOOS-PS and HOOS-PS were comparable to those of the WOMAC, Lequesne and NRS.
authors.affiliation: Rheumatology B Department, Cochin Hospital, Paris, France. adruyssen@hotmail.com
authors.forename: A
authors.initials: A
authors.lastname: Ruyssen-Witrand
authors.forename: C J
authors.initials: CJ
authors.lastname: Fernandez-Lopez
authors.forename: L
authors.initials: L
authors.lastname: Gossec
authors.forename: P
authors.initials: P
authors.lastname: Anract
authors.forename: J P
authors.initials: JP
authors.lastname: Courpied
authors.forename: M
authors.initials: M
authors.lastname: Dougados
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000503:physiopathology / Q000523:psychology*; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000523:psychology*; D010146:Pain / Q000503:physiopathology / Q000523:psychology*; D011594:Psychometrics / Q000379:methods* / Q000592:standards*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards