title: Severity and functional disability of patients with occupational contact dermatitis: validation of the German version of the Occupational Contact Dermatitis Disease Severity Index.
abstract: BACKGROUND
  The Occupational Contact Dermatitis Disease Severity Index (ODDI) was designed in Australia to measure severity and functional disability in patients with occupational contact dermatitis (OCD) of the hands. The ODDI was translated into the German language with a linguistic validation process. The psychometric properties of the German version of the ODDI are still unclear.
  
  
  OBJECTIVE
  To report the linguistic validation procedure and to perform a psychometric validation by investigating the validity and reliability of the German ODDI version in a sample of patients with OCD.
  
  
  METHODS
  Data were drawn from the baseline assessment (T0) and first follow-up (T1) of the German chronic hand eczema (CHE) registry (CARPE). Spearman correlations of the ODDI with reference measures were computed to assess validity. Cronbach's alpha was calculated as a measure of internal consistency, and the intraclass correlation coefficient (ICC) was calculated to assess retest reliability. The smallest real difference (SRD) and minimal clinically important difference (MCID) were calculated to assess sensitivity to change. Physician Global Assessment (PGA) was used as an anchor for the MCID.
  
  
  RESULTS
  Four hundred and twenty-two patients (54.5% female, mean age 45.1 years) were included for analysis. Cronbach's alpha was found to be 0.73. The ICC was 0.79. Correlations between the ODDI total and the Dermatology Life Quality Index (rho = 0.36), and between PGA (rho = 0.48) and patient-assessed disease severity (rho = 0.40), were of moderate strength. The MCID (1.29) was found to be smaller than the SRD (1.87).
  
  
  CONCLUSIONS
  The German ODDI version is reliable and valid for the measurement of functional impairment and disease severity in patients suffering from OCD.
authors.affiliation: Department of Clinical Social Medicine, University Hospital Heidelberg, Thibautstr. 3, 69115, Heidelberg, Germany.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Ofenloch
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Diepgen
authors.forename: Ana
authors.initials: A
authors.lastname: Popielnicki
authors.forename: Elke
authors.initials: E
authors.lastname: Weisshaar
authors.forename: Sonja
authors.initials: S
authors.lastname: Molin
authors.forename: Andrea
authors.initials: A
authors.lastname: Bauer
authors.forename: Vera
authors.initials: V
authors.lastname: Mahler
authors.forename: Peter
authors.initials: P
authors.lastname: Elsner
authors.forename: Jochen
authors.initials: J
authors.lastname: Schmitt
authors.forename: Christian
authors.initials: C
authors.lastname: Apfelbacher
mesh_terms: D000328:Adult; D000368:Aged; D009783:Dermatitis, Occupational / Q000175:diagnosis*; D004185:Disability Evaluation; D005260:Female; D006229:Hand Dermatoses / Q000175:diagnosis*; D006801:Humans; D008037:Linguistics; D008297:Male; D008875:Middle Aged; D011594:Psychometrics; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: disability; disease severity; minimal clinically important difference; occupational contact dermatitis; reliability; responsiveness to change; validity