title: Development of a new measure of health-related quality of life for people with dementia: DEMQOL.
abstract: BACKGROUND
  We identified the need to develop a scientifically rigorous measure of health-related quality of life (HRQL) in dementia that would be appropriate for use at all stages of dementia severity and would be available in both self- and proxy-report versions.
  
  
  METHODS
  We used standard psychometric methods to eliminate items with poor psychometric properties (item-reduction field test) and to assess the acceptability, reliability and validity of the item-reduced instruments (psychometric evaluation field test). We developed and validated two versions of DEMQOL: a 28-item interviewer-administered questionnaire that is self-reported by the person with dementia (DEMQOL) and a 31-item interviewer-administered questionnaire that is proxy-reported by a caregiver (DEMQOL-Proxy).
  
  
  RESULTS
  DEMQOL shows high reliability (internal consistency and test-retest) and moderate validity in people with mild/moderate dementia. DEMQOL-Proxy shows good acceptability and internal consistency and moderate evidence of validity in people with mild/moderate and severe dementia. Test-retest reliability and performance in people with severe dementia need further testing.
  
  
  CONCLUSIONS
  DEMQOL and DEMQOL-Proxy show psychometric properties that are comparable with the best available dementia-specific measures of HRQL. We recommend that DEMQOL and DEMQOL-Proxy are used together. Reliability and validity need to be confirmed in independent samples and responsiveness needs to be evaluated.
authors.affiliation: Health Services Research Department, Institute of Psychiatry, King's College London, UK.
authors.forename: S C
authors.initials: SC
authors.lastname: Smith
authors.forename: D L
authors.initials: DL
authors.lastname: Lamping
authors.forename: S
authors.initials: S
authors.lastname: Banerjee
authors.forename: R H
authors.initials: RH
authors.lastname: Harwood
authors.forename: B
authors.initials: B
authors.lastname: Foley
authors.forename: P
authors.initials: P
authors.lastname: Smith
authors.forename: J C
authors.initials: JC
authors.lastname: Cook
authors.forename: J
authors.initials: J
authors.lastname: Murray
authors.forename: M
authors.initials: M
authors.lastname: Prince
authors.forename: E
authors.initials: E
authors.lastname: Levin
authors.forename: A
authors.initials: A
authors.lastname: Mann
authors.forename: M
authors.initials: M
authors.lastname: Knapp
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D011594:Psychometrics; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires