title: Discriminant validity of the University of Washington quality of life questionnaire in the Brazilian context.
abstract: OBJECTIVE
  To assess discriminant validity of the University of Washington quality of life questionnaire for patients with head and neck cancer, and to identify socio-demographic factors that may modify its results.
  
  
  METHODS
  We interviewed 47 patients with oral and oropharyngeal cancer in pre-surgical stage in a hospital located in the South region of the city of São Paulo, in 2007, and 141 patients without cancer, matched by sex and age in a ratio of three to one, who were attending outpatient clinics of the same hospital in 2008. The results for the two groups were compared by the Student t test. Poisson regression models to evaluate factors that may modify quality of life scores among patients without cancer.
  
  
  RESULTS
  The overall quality of life score was significantly higher (p < 0.001) for patients without cancer (91.1) than for patients with cancer (80.6). Similar observations were made for eight of the twelve quality of life domains included in the questionnaire (pain, appearance, swallowing, chewing, speech, shoulder, taste, and anxiety). As factors that may modify the quality of life scores, we identified family income (which impacted in recreation, p = 0.017, and shoulder function, p = 0.049), schooling (in anxiety, p = 0.003), sex (in shoulder function, p = 0.038) and toothache (in chewing, p = 0.015).
  
  
  CONCLUSIONS
  The questionnaire has discriminant validity, because its scores are specifically more reduced among cancer patients. The use of the questionnaire for monitoring the treatment of cancer patients is reinforced, and the assessment of factors that may impact in its results is recommended.
authors.affiliation: Faculdade de Odontologia, Universidade de São Paulo, Brazil.
authors.forename: Fabiana Paula
authors.initials: FP
authors.lastname: de Andrade
authors.forename: Maria Gabriela Haye
authors.initials: MG
authors.lastname: Biazevic
authors.forename: Tatiana Natasha
authors.initials: TN
authors.lastname: Toporcov
authors.forename: Janina
authors.initials: J
authors.lastname: Togni
authors.forename: Marcos Brasilino
authors.initials: MB
authors.lastname: de Carvalho
authors.forename: José Leopoldo Ferreira
authors.initials: JL
authors.lastname: Antunes
mesh_terms: D001938:Brazil; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000175:diagnosis; D009959:Oropharyngeal Neoplasms / Q000175:diagnosis; D011788:Quality of Life; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires