title: Using patients' and rheumatologists' opinions to specify a short form of the WOMAC function subscale.
abstract: BACKGROUND
  The WOMAC (Western Ontario and McMaster Universities) function subscale is widely used in clinical trials of hip and knee osteoarthritis. Reducing the number of items of the subscale would enhance efficiency and compliance, particularly for use in clinical practice applications.
  
  
  OBJECTIVE
  To develop a short form of the WOMAC function subscale based on patients' and experts' opinions (WOMAC function short form).
  
  
  METHODS
  WOMAC function subscale data (Likert version) were obtained from 1218 outpatients with painful hip or knee osteoarthritis. These patients and their rheumatologists selected the five items that they considered most in need of improvement. The rheumatologists were asked to select the five items for which patients in general are the most impaired. Items that were least important to patients and experts, those with a high proportion of missing data, and those with a response distribution showing a floor or ceiling response were excluded, along with one of a pair of items with a correlation coefficient >0.75.
  
  
  RESULTS
  The WOMAC function short form included items 1, 2, 3, 6, 7, 8, 9, and 15 of the long form. The short form did not differ substantially from the long form in responsiveness (standardised response mean of 0.84 v 0.80).
  
  
  CONCLUSIONS
  A short form of the WOMAC function subscale was developed according to the views of patients and rheumatologists, based on the responses of 1218 patients and 399 rheumatologists. The clinical relevance and applicability of this WOMAC function subscale short form require further evaluation.
authors.affiliation: Département d'Epidémiologie, Biostatistique et Recherche Clinique, Groupe Hopitalier Bichat-Claude Bernard, 75018 Paris, France. florence.tubach@bch.ap-hop-paris.fr
authors.forename: F
authors.initials: F
authors.lastname: Tubach
authors.forename: G
authors.initials: G
authors.lastname: Baron
authors.forename: B
authors.initials: B
authors.lastname: Falissard
authors.forename: I
authors.initials: I
authors.lastname: Logeart
authors.forename: M
authors.initials: M
authors.lastname: Dougados
authors.forename: N
authors.initials: N
authors.lastname: Bellamy
authors.forename: P
authors.initials: P
authors.lastname: Ravaud
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D001291:Attitude of Health Personnel; D001294:Attitude to Health; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000503:physiopathology*; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D011446:Prospective Studies; D015203:Reproducibility of Results