How does the EQ-5D perform when measuring quality of life in dementia against two other dementia-specific outcome measures?
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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.
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 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.
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.
KeywordsEQ-5D Dementia Utility DEMQoL QoL-AD Quality of life
Maintenance Cognitive Stimulation Programme (ISRCTN26286067) is part of the Support at Home—Interventions to Enhance Life in Dementia (SHIELD) project (Application No. RP-PG-0606-1083) which is funded by the NIHR Programme Grants for Applied research funding scheme. The grant holders are Professors Orrell (UCL), Woods (Bangor), Challis (Manchester), Moniz-Cook (Hull), Russell (Swansea), Knapp (LSE) and Dr Charlesworth (UCL). The views and opinions expressed in this paper are those of the authors and do not necessarily reflect those of the Department of Health/NIHR.
Compliance with Ethical Standards
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
This study was funded by the NIHR Programme Grants for Applied research funding scheme as part of the Support at Home—Interventions to Enhance Life in Dementia (SHIELD) project (Application No. RP-PG-0606-1083).
Conflict of interest
The authors declare that they have no conflict of interest.
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