title: Performance of the EQ-5D and the EQ-5D+C in elderly patients with cognitive impairments.
abstract: BACKGROUND
  The EQ-5D is a reliable tool for measuring Health-Related Quality of Life (HRQoL). However, concern has been expressed that it may ignore elements of HRQoL, particularly cognition. In response to this concern, the EQ-5D has been extended with a cognitive dimension (EQ-5D+C). The aim of this study was to compare the performance of the EQ-5D and the EQ-5D+C in elderly patients with cognitive impairments by assessing their construct validity and responsiveness.
  
  
  METHODS
  Data from the MEDICIE study (n = 196) were used, in which all questionnaires were rated by proxies.
  
  
  RESULTS
  Regarding construct validity, we found similar correlations between the EQ-5D and the Mini Mental State Examination (MMSE) and between the EQ-5D+C and the MMSE. Furthermore, both the EQ-5D and the EQ-5D+C were responsive to changes in the MMSE, with the EQ-5D performing slightly better.
  
  
  CONCLUSIONS
  We conclude that the EQ-5D performs well for evaluating HRQoL in a population with cognitive impairments. Based on the results of this explorative study, it does not seem necessary to adjust the current classification system by adding a cognitive dimension. However, in order to compare both instruments regarding utility values, it is necessary to develop a new scoring algorithm for the EQ-5D+C by conducting a general population study. Considering the explorative nature of this study, it is recommended that more aspects of the validity of both the EQ-5D and the EQ-5D+C are explored in patients with cognitive impairments using a more tailored study design.
authors.affiliation: Department of Clinical Epidemiology and Medical Technology Assessment, Maastricht University Hospital, Maastricht, Netherlands. claire.wolfs@np.unimaas.nl
authors.forename: Claire A G
authors.initials: CA
authors.lastname: Wolfs
authors.forename: Carmen D
authors.initials: CD
authors.lastname: Dirksen
authors.forename: Alfons
authors.initials: A
authors.lastname: Kessels
authors.forename: Daniëlle C M
authors.initials: DC
authors.lastname: Willems
authors.forename: Frans R J
authors.initials: FR
authors.lastname: Verhey
authors.forename: Johan L
authors.initials: JL
authors.lastname: Severens
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017028:Caregivers; D003072:Cognition Disorders / Q000145:classification / Q000503:physiopathology* / Q000523:psychology; D003704:Dementia / Q000145:classification / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D009483:Neuropsychological Tests; D017064:Process Assessment, Health Care; D019727:Proxy; D011594:Psychometrics / Q000295:instrumentation*; D011788:Quality of Life; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires / Q000592:standards*