How Different are Quality of Life Ratings for People with Dementia Reported by Their Family Caregivers from Those Reported by the Patients Themselves?

BACKGROUND

Measurements of patient quality of life (QoL) play a major role in the management of dementia.

OBJECTIVE

We investigated the self-proxy discrepancy of QoL ratings in the elderly and the impact of dementia severity on the discrepancy.

METHODS

QoL of 718 patients with dementia and 651 non-demented elderly were rated by themselves and their caregivers (CG) using the Quality of Life-Alzheimer's Disease (QoL-AD). The impact of the rater on the total and item scores of QoL-AD was analyzed using repeated measures ANOVA and differential response patterns between self and proxy were analyzed using differential item functioning (DIF) analysis.

RESULTS

Self-rated scores were higher than CG-rated scores in all diagnostic groups. The interaction between rater and diagnostic group was significant in total QoL-AD score and 5 item scores ('memory', 'marriage', 'chores around the house', 'do things for fun', and 'life as a whole'). The strength of the DIF increased with advancing dementia in these items.

CONCLUSION

Self-proxy rating discrepancy of QoL was influenced by the presence and severity of dementia only in five items.