Can people with mild to moderate dementia provide reliable answers about their quality of life?

BACKGROUND: Cognitive limitations and lack of insight have been seen as barriers to self-reporting in quality of life (QoL) assessment of people with dementia. However growing evidence suggests that people with mild to moderate dementia may be able to complete standardised questionnaire items and articulate feelings, providing reliable evaluations of their health and QoL. OBJECTIVE: To examine the reliability of the item pool of a new measure of self-reported QoL, the Bath Assessment of Subjective Quality of Life in Dementia (BASQID). SUBJECTS: Sixty people with mild to moderate dementia, recruited from a memory clinic. METHODS: Participants completed 44 items from an initial draft of the BASQID and 30 completed the items on a second occasion, 2 weeks later. Item analytic criteria, including item facility, score distributions, tests of internal consistency and reproducibility, were used to reduce the item pool, and the reliability of the reduced pool was examined. RESULTS: Twenty items were removed from the item pool. All retained items had at least moderate test-retest reliability (kappa >0.41), with 13 items displaying good to very good reliability (kappa >0.61). These 24 items were internally consistent (alpha = 0.91), and the total score had a good 2-week test-retest reliability with an intraclass correlation coefficient of 0.82 (0.66-0.91). CONCLUSIONS: Participants were able to complete items relating to feelings and evaluations of a range of QoL domains. The consistency of responses over a 2-week period suggests that self-reported QoL assessments are feasible and appropriate for people with mild to moderate dementia.