Exploring older people's understanding of the QOL-ACC, a new preference-based quality-of-life measure, for quality assessment and economic evaluation in aged care: the impact of cognitive impairment and dementia.

BACKGROUND: Quality-of-life is an essential outcome for quality assessment and economic evaluation in health and social care. The-Quality-of-Life - Aged Care Consumers (QOL-ACC) is a new preference-based quality-of-life measure, psychometrically validated with older people in aged care. More evidence is needed to inform the self-report reliability of the QOL-ACC in older people with varying levels of cognitive impairment and dementia.

METHODS: A think-aloud protocol was developed and applied with older residents. The Mini Mental State Examination (MMSE) was applied to assign participants to no cognitive impairment (NCI - MMSE score ≥ 27) and cognitive impairment (MMCI - MMSE score < 27) subgroups. Three independent raters utilised a Tourangeau survey response model-based framework to identify response issues. Data were compared across cognition subgroups and synthesized using a 'traffic light' grading to classify frequency and type of response issues. Gradings were utilised to assess self-report reliability according to different levels of cognitive impairment.

RESULTS: Qualitative data from 44 participants (NCI = 20, MMCI = 24) were included for analysis. Response issues were more evident in the cognitive impairment subgroup than the no cognitive impairment subgroup. All participants who received a 'red' grade had an MMSE score of < 20 and 66% of 'amber' grades occurred in the cognitive impairment subgroup.

CONCLUSIONS: The QOL-ACC is able to be completed reliably by older residents with an MMSE score > 17. Future research is needed to assess the generalisability of these findings to other preference-based quality of life instruments and for older people in other care settings including health systems.