Measuring the outcomes of long-term care for unpaid carers: comparing the ASCOT-Carer, Carer Experience Scale and EQ-5D-3 L

Background: The ASCOT-Carer and Carer Experience Scale are instruments designed to capture aspects of quality of life 'beyond health' for family carers. The aim of this study was to compare and validate these two carer care-related measures, with a secondary aim to compare both instruments to the three-level EQ-5D (EQ-5D-3 L) measure of health-related quality of life.

Methods: An interview survey was conducted with 387 carers of adults who used long-term care (also known as social care) support in England. Construct validity by hypothesis testing was assessed using Pearson correlation coefficient. Exploratory factor analysis was also applied to investigate the dimensionality of the combined items from the ASCOT-Carer and CES (as measures of carer quality of life 'beyond health') and the EQ-5D (as a measure of health-related quality of life).

Results: In the construct validity analysis, hypothesised differences in correlations were observed with two exceptions. The exploratory factor analysis indicated that the ASCOT-Carer, CES and EQ-5D-3 L items loaded onto three separate factors. The first factor comprised the seven ASCOT-Carer items plus two CES items (activities outside caring, support from friends and family). The second factor comprised three of the six CES items (fulfilment from caring, control over caring and getting on with the person you care for). The third factor included four of the five EQ-5D-3 L items.

Conclusion: The findings indicate that the ASCOT-Carer, CES and EQ-5D-3 L capture separate constructs of social care-related quality of life (ASCOT-Carer) and carer experience (CES), which partially overlap in relation to activities outside caring and social support, and health-related quality of life (EQ-5D-3 L). The ASCOT-Carer and CES are both promising measures for the evaluation of social care support for carers that capture aspects of quality of life 'beyond health'. The choice of whether to use the ASCOT-Carer or CES depends on the study objectives.