title: Validation of an instrument to measure quality of life in British children with inflammatory bowel disease.
abstract: OBJECTIVE
  To validate IMPACT-III (UK), a health-related quality of life (HRQoL) instrument, in British children with inflammatory bowel disease (IBD).
  
  
  METHODS
  One hundred six children and parents were invited to participate. IMPACT-III (UK) was validated by inspection by health professionals and children to assess face and content validity, factor analysis to determine optimum domain structure, use of Cronbach alpha coefficients to test internal reliability, ANOVA to assess discriminant validity, correlation with the Child Health Questionnaire to assess concurrent validity, and use of intraclass correlation coefficients to assess test-retest reliability. The independent samples t test was used to measure differences between sexes and age groups, and between paper and computerised versions of IMPACT-III (UK).
  
  
  RESULTS
  IMPACT-III (UK) had good face and content validity. The most robust factor solution was a 5-domain structure: body image, embarrassment, energy, IBD symptoms, and worries/concerns about IBD, all of which demonstrated good internal reliability (α = 0.74-0.88). Discriminant validity was demonstrated by significant (P  < 0.05, P < 0.01) differences in HRQoL scores between the severe, moderate, and inactive/mild symptom severity groups for the embarrassment scale (63.7 vs 81.0 vs 81.2), IBD symptom scale (45.0 vs 64.2 vs 80.6), and the energy scale (46.4 vs 62.1 vs 77.7). Concurrent validity of IMPACT-III (UK) with comparable domains of the Child Health Questionnaire was confirmed. Test-retest reliability was confirmed with good intraclass correlation coefficients of 0.66 to 0.84. Paper and computer versions of IMPACT-III (UK) collected comparable scores, and there were no differences between the sexes and age groups.
  
  
  CONCLUSIONS
  IMPACT-III (UK) appears to be a useful tool to measure HRQoL in British children with IBD.
authors.affiliation: University of Central Lancashire, Preston, Lancaster, UK.
authors.forename: C A
authors.initials: CA
authors.lastname: Ogden
authors.forename: A K
authors.initials: AK
authors.lastname: Akobeng
authors.forename: J
authors.initials: J
authors.lastname: Abbott
authors.forename: P
authors.initials: P
authors.lastname: Aggett
authors.forename: M R
authors.initials: MR
authors.lastname: Sood
authors.forename: A G
authors.initials: AG
authors.lastname: Thomas
mesh_terms: D000293:Adolescent; D001007:Anxiety / Q000453:epidemiology / Q000523:psychology*; D001828:Body Image; D002648:Child; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000453:epidemiology / Q000473:pathology / Q000523:psychology*; D008297:Male; D011788:Quality of Life / Q000523:psychology*; D011795:Surveys and Questionnaires; D006113:United Kingdom / Q000453:epidemiology; D044465:White People