title: How does the EQ-5D perform when measuring quality of life in dementia against two other dementia-specific outcome measures?
abstract: OBJECTIVE
  This study aimed to assess and compare the psychometric performance of the EQ-5D in relation to other dementia-specific measures, the QoL-AD and DEMQoL, within a psychosocial intervention study.
  
  
  METHODS
  Two hundred and seventy-two people with dementia completed the EQ-5D, DEMQoL and QoL-AD. Convergent and discriminant validity of the measures were assessed, and inter-rater reliability was tested by comparing the self-reported and proxy scores of the measures. Internal consistency was tested using Cronbach's alpha.
  
  
  RESULTS
  Results satisfy convergent validity amongst the three outcome measures. EQ-5D, DEMQoL and QoL-AD total scores were shown to be significantly correlated with each other (p < 0.001) in both participants with dementia and proxy reports. Results also satisfied discriminant validity for participant EQ-5D, DEMQoL and QoL-AD total scores. In relation to reliability between self and proxy scores, the EQ-5D showed higher reliability scores between participant and proxy total scores for mild and moderate level of cognitive impairment and performed better than the dementia-specific measures. Reliability assessed through Cronbach's alpha was satisfactory, indicating adequate internal consistency of all three measures.
  
  
  CONCLUSIONS
  The results suggest that the EQ-5D might have advantages over other dementia-specific measures, and it could be used routinely and as a stand-alone measure of quality of life in dementia research.
authors.affiliation: Division of Psychiatry, University College London, Charles Bell House, 67-73 Riding House Street, London, W1W 7EJ, England, UK. e.aguirre@ucl.ac.uk.
authors.forename: Elisa
authors.initials: E
authors.lastname: Aguirre
authors.affiliation: Division of Psychiatry, University College London, Charles Bell House, 67-73 Riding House Street, London, W1W 7EJ, England, UK. s.kang@bangor.ac.uk.
authors.forename: Sujin
authors.initials: S
authors.lastname: Kang
authors.affiliation: Division of Psychiatry, University College London, Charles Bell House, 67-73 Riding House Street, London, W1W 7EJ, England, UK. z.hoare@bangor.ac.uk.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Hoare
authors.affiliation: Division of Psychiatry, University College London, Charles Bell House, 67-73 Riding House Street, London, W1W 7EJ, England, UK. r.t.edwards@bangor.ac.uk.
authors.forename: Rhiannon Tudor
authors.initials: RT
authors.lastname: Edwards
authors.affiliation: Division of Psychiatry, University College London, Charles Bell House, 67-73 Riding House Street, London, W1W 7EJ, England, UK. m.orrell@ucl.ac.uk.
authors.forename: Martin
authors.initials: M
authors.lastname: Orrell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003704:Dementia / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011594:Psychometrics / Q000379:methods*; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires
keywords: DEMQoL; Dementia; EQ-5D; QoL-AD; Quality of life; Utility