EQ-5D as a Quality of Life Measure in People with Dementia and Their Carers: Evidence and Key Issues

Objectives: This article analyzes published studies on the application of the EQ-5D for the assessment of quality of life in patients with dementia and their carers. The EQ-5D, a generic instrument for measuring health-related quality of life, is widely used for economic evaluation in many areas of health research. However, there is considerable debate about the appropriateness of the EQ-5D for people with impaired cognition. Methods: We conducted a systematic review of research studies published in the past 10 years that either used the EQ-5D as an outcome measure or investigated different aspects of the performance of the EQ-5D in studies of dementia. Results: This study demonstrates that despite good feasibility and reliability of the EQ-5D instrument, there are problems with the validity of self-rated data because of a lack of association between patient and proxy ratings. There is a substantial ceiling effect for patient ratings. The visual analogue scale has poor reliability, even in patients with mild and moderate dementia. Different proxies (e. g., family carers, institutional carers, and healthcare professionals) provide different ratings for patients' health. Conclusion: Careful selection of assessment mode and appropriate proxies is important to ensure the EQ-5D validity in studies of patients with dementia. Because the cost of informal patient care represents a significant proportion of total costs of dementia treatment, the impact of dementia on carer's quality of life should be included in economic evaluation. Copyright (C) 2011, International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc.