title: The laval questionnaire: a new instrument to measure quality of life in morbid obesity.
abstract: BACKGROUND
  Our recent review of the literature uncovered eleven obesity-specific quality of life questionnaires, all with incomplete demonstration of their measurement properties. Our objective was to validate a new self-administered questionnaire specific to morbid obesity to be used in clinical trials. The study was carried out at the bariatric surgery clinic of Laval Hospital, Quebec City, Canada.
  
  
  METHODS
  This study followed our description of health-related quality of life in morbid obesity from which we constructed the Laval Questionnaire. Its construct validity and responsiveness were tested by comparing the baseline and changes at 1-year follow-up in 6 domain scores (symptoms, activity/mobility, personal hygiene/clothing, emotions, social interactions, sexual life) with those of questionnaires measuring related constructs (SF-36, Impact of Weight on Quality of Life-Lite, Rosenberg Self-Esteem Scale and Beck Depression Inventory-II).
  
  
  RESULTS
  112 patients (67 who got bariatric surgery, 45 who remained on the waiting list during the study period) participated in this study. The analysis of the discriminative function of the questionnaire showed moderate-to-high correlations between the scores in each domain of our instrument and the corresponding questionnaires. The analysis of its evaluative function showed (1) significant differences in score changes between patients with bariatric surgery and those without, and (2) moderate-to-high correlations between the changes in scores in the new instrument and the changes in the corresponding questionnaires. Most of these correlations met the a priori predictions we had made regarding their direction and magnitude.
  
  
  CONCLUSIONS
  The Laval Questionnaire is a valid measure of health-related quality of life in patients with morbid obesity and is responsive to treatment-induced changes.
authors.affiliation: Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec affilié à l'Université Laval, 2725 Chemin Ste-Foy, Québec, Québec G1V 4G5, Canada. yves.lacasse@med.ulaval.ca
authors.forename: Fanny
authors.initials: F
authors.lastname: Therrien
authors.forename: Picard
authors.initials: P
authors.lastname: Marceau
authors.forename: Nathalie
authors.initials: N
authors.lastname: Turgeon
authors.forename: Simon
authors.initials: S
authors.lastname: Biron
authors.forename: Denis
authors.initials: D
authors.lastname: Richard
authors.forename: Yves
authors.initials: Y
authors.lastname: Lacasse
mesh_terms: D000328:Adult; D050110:Bariatric Surgery / Q000523:psychology*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D015897:Comorbidity; D003863:Depression / Q000175:diagnosis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000523:psychology* / Q000601:surgery; D011788:Quality of Life; D011792:Quebec; D015203:Reproducibility of Results; D012649:Self Concept; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires; D014850:Waiting Lists