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.