The use of the EQ-5D as a measure of health-related quality of life in people with dementia and their carers.

PURPOSE

To assess the acceptability, validity and inter-rater agreement of self- and family carer proxy ratings of the EQ-5D as a generic health-related quality of life (HRQOL) measure, in people with mild to moderate dementia (PwD) living in the community. A secondary aim was to identify the most important factors influencing self- and family carer proxy ratings of HRQOL, distinguishing between spouse and adult child caregiver ratings.

METHODS

Cross-sectional study of 488 dyads using the EQ-5D. Inter-rater agreement was examined using weighted kappa scores, and validity by investigating the association of self- and family carer ratings with clinical variables. Factors affecting HRQOL ratings were analysed using multivariate regression.

RESULTS

The response rate of the EQ-5D was satisfactory; however, agreement between self- and family carer ratings was poor. The most important predictors of PwD and carer ratings of the PwD's HRQOL were family carer ratings of activities of daily living and mood. Anxiety experienced by the PwD was a significant predictor of self-rated HRQOL, whereas depressive symptoms independently predicted family carer ratings. The type of the caregiving relationship influenced carer ratings of HRQOL, whereby sons and daughters rated HRQOL lower for the PwD compared with spousal caregivers.

CONCLUSIONS

People with mild to moderate dementia are able to rate their own HRQOL through a brief generic instrument; however, self-ratings consistently differ from family carer ratings, which should be acknowledged in cost-effectiveness analyses. Spouse caregivers rate HRQOL for the PwD more positively compared to adult children.