Potential of ASCOT-Carer for evaluating the quality of life of family caregivers for patients with Alzheimer's disease in Japan.

PURPOSE: We explored the suitability of the Adult Social Care Outcomes Toolkit for Carers (ASCOT-Carer) against the widely used EQ-5D for evaluating the quality of life (QoL) of Japanese caregivers of patients with Alzheimer’s disease. This research aimed to expand the available preference-based measures for assessing caregiver QoL in health economic evaluations in Japan. METHODS: This was a cross-sectional survey using a web-based questionnaire. The alignment between the ASCOT-Carer and established measures, as well as its construct alignment, were evaluated. These were respectively investigated through Pearson’s correlation analysis with the EQ-5D-5L and factor analysis using the EQ-5D-5L and the eight-item short Japanese version of the Zarit Burden Interview (J_ZBI-8). RESULTS: In total, 705 live-in family caregivers of patients with Alzheimer’s disease completed the main survey. The absolute correlation coefficients were between J_ZBI-8 and EQ-5D-5L scores, + 0.268; between J_ZBI-8 and ASCOT-Carer scores, + 0.472; and between EQ-5D-5L and ASCOT-Carer scores, + 0.463. Factor analysis revealed that the only factors showing moderate/stronger correlations with factors constituted by J_ZBI-8 were those derived from ASCOT-Carer (inter-factor correlation: +0.31 and + 0.50). The ASCOT-Carer was a more important variable relative to the EQ-5D-5L for measuring caregivers’ QoL related to caregiver burden. CONCLUSION: The ASCOT-Carer may be a more suitable tool for evaluating the impact of caregiving burden on caregivers’ QoL. When incorporating QoL based on caregiver burden in health economic evaluations, the ASCOT-Carer may be an appropriate option.