title: The clinimetric properties of the World Health Organization Disability Assessment Schedule II in early inflammatory arthritis.
abstract: OBJECTIVE
  To assess the clinimetric properties of a new health-related quality of life (HRQOL) instrument, the World Health Organization Disability Assessment Schedule II (WHODAS II), in patients with early inflammatory arthritis.
  
  
  METHODS
  Internal consistency as well as criterion, construct, and discriminative validity of the WHODAS II were assessed in 172 patients with early inflammatory arthritis who completed the WHODAS II, the Medical Outcomes Study Short Form 36 (SF-36), and other measures of disease severity, functioning, pain, depression, and resource use. Test-retest reliability of the WHODAS II was assessed by having a subset of 20 patients complete the WHODAS II a second time, 1 week after the first assessment.
  
  
  RESULTS
  The WHODAS II had high internal consistency (Cronbach's alpha = 0.96 for patients working or in school and 0.93 for patients not working or in school). Test-retest intraclass correlation coefficients of the WHODAS II total score and subscales ranged from 0.82-0.96. The WHODAS II total score was strongly correlated with the SF-36 physical component score (Kendall's tau-b 0.51, P < 0.001) and moderately correlated with the SF-36 mental component score (tau-b 0.43, P < 0.001). WHODAS II correlations with disease outcomes ranged from Kendall's tau-b 0.15-0.55. The WHODAS II significantly differentiated between every aspect of disease severity assessed with the exception of measures of health resource use.
  
  
  CONCLUSIONS
  The WHODAS II is a valid and reliable measure of HRQOL in cross-sectional studies of patients with early inflammatory arthritis. Research is still required to investigate potential item redundancy and determine its usefulness in longitudinal studies.
authors.affiliation: McGill University, Montreal, Quebec, Canada. mbaron@rhu.jgh.mcgill.ca
authors.forename: Murray
authors.initials: M
authors.lastname: Baron
authors.forename: Orit
authors.initials: O
authors.lastname: Schieir
authors.forename: Marie
authors.initials: M
authors.lastname: Hudson
authors.forename: Russell
authors.initials: R
authors.lastname: Steele
authors.forename: Sousan
authors.initials: S
authors.lastname: Kolahi
authors.forename: Laeora
authors.initials: L
authors.lastname: Berkson
authors.forename: Francois
authors.initials: F
authors.lastname: Couture
authors.forename: M A
authors.initials: MA
authors.lastname: Fitzcharles
authors.forename: Michel
authors.initials: M
authors.lastname: Gagné
authors.forename: Bruce
authors.initials: B
authors.lastname: Garfield
authors.forename: Andrzej
authors.initials: A
authors.lastname: Gutkowski
authors.forename: Harb
authors.initials: H
authors.lastname: Kang
authors.forename: Morton
authors.initials: M
authors.lastname: Kapusta
authors.forename: Sophie
authors.initials: S
authors.lastname: Ligier
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Mathieu
authors.forename: Henri
authors.initials: H
authors.lastname: Ménard
authors.forename: Michael
authors.initials: M
authors.lastname: Starr
authors.forename: Michael
authors.initials: M
authors.lastname: Stein
authors.forename: Michel
authors.initials: M
authors.lastname: Zummer
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications*; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D012720:Severity of Illness Index; D014944:World Health Organization