Quality-of-life in dementia: Assessment in low-and-middle income countries
The global burden of dementia is disproportionately higher in low-and-middle income countries yet systematic assessments of health-related quality-of-life (HRQL) mostly rely on measures developed in the UK/US. A recent systematic review of dementia-specific HRQL measures concluded that none could be recommended without further linguistic validation. Using a unique dataset from the 10/66 Dementia Research Group, we conducted one of the first in-depth studies to investigate the measurement invariance of dementia-specific HRQL measures for low-and-middle income countries. HRQL of people with dementia was assessed by self-report (DEMQOL) and informant-report (DEMQOL-Proxy) in a community memory clinic in the UK and population cohort surveys of the 10/66 Dementia Research Group in the Dominican Republic, Mexico, Cuba, Peru and Venezuela. Measurement invariance between the UK English and Ibero-American Spanish versions was investigated using multiple-group confirmatory bifactor modelling. Our findings showed that UK and Latin America older adults differ in how they respond to “positive emotion” items in the DEMQOL and DEMQOL-Proxy. The remaining items of DEMQOL and DEMQOL-Proxy showed no major difference in conceptual meaning, sensitivity to individual differences, and standards of difficulty between the UK English and Ibero-American Spanish versions. Furthermore, we found that the core components of self- and informant appraisal of HRQL may differ. Negative emotion may be a core component in self-appraisal of HRQL whereas social functioning may be a core component in how informants appraise HRQL of people with dementia. Measurement invariance of translated HRQL assessment warrant continued investigation, particularly in low-and-middle income countries, where the societal and fiscal impact of dementia needs urgent attention.