title: Rasch analysis of the Hospital Anxiety and Depression Scale in spinal cord injury.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the psychometric properties of the Hospital Anxiety and Depression Scale (HADS), applied among persons with spinal cord injury (SCI), using Rasch analysis.
  
  
  METHODS
  A cross-sectional multicenter study was conducted and the data of 102 people with SCI were analyzed. Rasch analyses were performed to assess dimensionality, overall and individual item fit, response scale structure, targeting, and differential item functioning.
  
  
  RESULTS
  The anxiety and depression subscales showed unidimensionality, that is, model and item fit. The two subscales are reliable (r = .72, 0.82) in SCI. No disordered structure of the response scales or differential item functioning in age, gender, education, relationship status, level of spinal lesion were found. Stepwise deletion of the misfitting items did not produce a total score that fulfilled the statistical criteria for unidimensionality.
  
  
  CONCLUSIONS
  The results of the Rasch analyses support the use of the anxiety and depression subscales among people with SCI. However, further research is needed to confirm these findings and examine sensitivity to change of the HADS in SCI, which would support its use in longitudinal observational and intervention studies.
authors.affiliation: Swiss Paraplegic Research (SPF), Guido A. Zäch Strasse 4, CH-6207 Nottwil, Switzerland. rachel.mueller@paranet.ch
authors.forename: Rachel
authors.initials: R
authors.lastname: Müller
authors.forename: Alarcos
authors.initials: A
authors.lastname: Cieza
authors.forename: Szilvia
authors.initials: S
authors.lastname: Geyh
mesh_terms: D001008:Anxiety Disorders / Q000175:diagnosis*; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011581:Psychological Tests; D011594:Psychometrics; D015203:Reproducibility of Results; D013119:Spinal Cord Injuries / Q000523:psychology* / Q000534:rehabilitation; D013315:Stress, Psychological / Q000175:diagnosis; D011795:Surveys and Questionnaires; D013557:Switzerland