title: Measures of relative importance for health-related quality of life.
abstract: OBJECTIVE
  In health-related quality of life (HRQOL) studies, data are often collected on multiple domains for two or more groups of study participants. Quantitative measures of relative importance, which are used to rank order the domains based on their ability to discriminate between groups, are an alternative to multiple tests of significance on the group differences. This study describes relative importance measures based on logistic regression (LR) and multivariate analysis of variance (MANOVA) models.
  
  
  METHODS
  Relative importance measures are illustrated using data from the Manitoba Inflammatory Bowel Disease (IBD) Cohort Study. Study participants with self-reported active (n = 244) and inactive (n = 105) disease were compared on 12 HRQOL domains from the Inflammatory Bowel Disease Questionnaire (IBDQ) and Medical Outcomes Study 36-item Short-Form (SF-36) Questionnaire.
  
  
  RESULTS
  All but two relative importance measures ranked the IBDQ bowel symptoms and emotional health domains as most important.
  
  
  CONCLUSIONS
  MANOVA-based importance measures are recommended for multivariate normal data and when group covariances are equal, while LR measures are recommended for non-normal data and when the correlations among the domains are small. Relative importance measures can be used in exploratory studies to identify a small set of domains for further research.
authors.affiliation: School of Public Health, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada.
authors.forename: Tolulope T
authors.initials: TT
authors.lastname: Sajobi
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Lix
authors.forename: Ian
authors.initials: I
authors.lastname: Clara
authors.forename: John
authors.initials: J
authors.lastname: Walker
authors.forename: Lesley A
authors.initials: LA
authors.lastname: Graff
authors.forename: Patricia
authors.initials: P
authors.lastname: Rawsthorne
authors.forename: Norine
authors.initials: N
authors.lastname: Miller
authors.forename: Linda
authors.initials: L
authors.lastname: Rogala
authors.forename: Rachel
authors.initials: R
authors.lastname: Carr
authors.forename: Charles N
authors.initials: CN
authors.lastname: Bernstein
mesh_terms: D000328:Adult; D002170:Canada; D015331:Cohort Studies; D005260:Female; D006304:Health Status; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000503:physiopathology / Q000523:psychology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011788:Quality of Life / Q000523:psychology*; D011795:Surveys and Questionnaires / Q000592:standards