Determining the predictors of change in quality of life self-ratings and carer-ratings for community-dwelling people with Alzheimer disease.

The aim of this study was to determine the factors that mediate changes in Health Related Quality of Life (HRQoL) ratings by community-dwelling people with Alzheimer disease (AD) and carers over a period of 18 months. We completed an 18-month longitudinal study of 80 community-dwelling older adults diagnosed with probable AD of mild or moderate severity (NINCDS-ADRD criteria) and their family carers. The primary outcome of interest was the 18-month change in HRQoL ratings as measured with the Quality of Life-AD (QoL-AD) (by carer and by self). Explanatory variables included demographics, lifestyle, cognition, awareness, psychopathology, burden-of-care, use of medication, and functionality in daily life. We found a significant decline (8.7%, P=0.003) in QoL-AD carer-ratings, but not in self-ratings. The final parsimonious model of predictors of changes in QoL-AD self-ratings explained 22.6% of the variance; only changes on Hospital Anxiety and Depression Scale Anxiety retained significance. The final model of predictors of changes in carer-ratings explained 55.0% of the variance: that is, changes on Informant Questionnaire on Cognitive Decline in the Elderly, changes on Hospital Anxiety and Depression Scale Depression, practicing hobbies at 18 months, and number of visit(s) or admission(s) to hospital. HRQoL self-ratings and carer-ratings of community-dwelling people with AD do not decline at same rate over 18 months and changes are associated with different factors. Interventions designed to optimize quality of life of people with AD should consider carefully whose HRQoL ratings they wish to change.