Assessing the psychometric performance of the EQ-5D-5L among informal caregivers of people with dementia

Purpose: This study aimed to examine the psychometric performance of the EQ-5D-5L in informal caregivers of people with dementia.

Methods: Data were obtained from an online survey administered to informal caregivers of people with dementia in Australia. Known-group comparisons were examined by formulating 15 a priori hypotheses, where a difference was made between weak and strong hypotheses. Group comparisons were tested using the non-parametric Wilcoxon-rank and the Kruskal-Wallis test, as well as regression analysis. Floor and ceiling effects were considered to be present if more than 15% of respondents achieved the lowest or highest possible score, respectively.

Results: In total, 212 informal caregivers of people with dementia were included in the analysis. On average, participants were 47 years old (SD: 17) and 61% of them were female. The mean EQ-5D-5L utility score was 0.88 (SD: 0.16) and the mean EQ-VAS was 72.47 (SD: 17.86). While there was no floor effect, 26% reported full health. Nine strong and three weak hypotheses were confirmed, supporting the ability of the EQ-5D-5L to discriminate between groups with respect to: self-reported health status, happiness levels, presence of mental or physical health conditions, ability to engage in enjoyable activities, and availability of support.

Conclusion: Findings provide supporting evidence for the EQ-5D-5L in terms of its discriminant validity in informal caregivers of patients with dementia. However, the present ceiling effect suggests that the sensitivity of the EQ-5D-5L to detect improvements may be limited. Further studies are warranted examining other psychometric criteria, including reliability and responsiveness to change.