Can EuroQol Instruments be Used to Study Climate Change? Validity and Responsiveness of the EQ-5D-5L, EQ-HWB and EQ-HWB-S to Measure Health and Wellbeing Impact of Heatwaves Among Older Adults

OBJECTIVES: To assess the validity and responsiveness of EQ-5D-5L, EQ-HWB and EQ-HWB-S for measuring the health and wellbeing impact of heatwaves among older adults.

METHODS: A cohort of residents aged≥60 living in Fuzhou city, China, were surveyed four times: before summer in May, during heatwaves in June to July and August, and after summer in October, 2023. At all timepoints, the EQ-HWB, EQ-5D-5L and self-designed questions assessing self-perceived effects of heatwaves were administered through one-on-one, face-to-face interviews. We examined the known-group validity (using Cohen’s d effect sizes) and responsiveness (using standardized response mean[SRM]) of EQ-5D-5L, EQ-HWB and EQ-HWB-S scores (including index values and level sum scores[LSS]). We used multivariate random effects models to explore the temporal effects of heatwaves on EQ-5D-5L, EQ-HWB and EQ-HWB-S scores.

RESULTS: A total of 579, 510, 473 and 508 residents completed the first, second, third and fourth waves of survey, respectively. During heatwaves, respondents who did not have excessive sweating or were adapted to weather had higher EQ-5D-5L and EQ-HWB-S index values, and lower EQ-HWB LSS compared to those having excessive sweating or not adapted to weather, respectively, with the effect size being negligible to small (Cohen's d:0.08 to 0.40 for EQ-5D-5L; 0.16 to 0.34 for EQ-HWB-S; 0.28 to 0.45 for EQ-HWB). All the EQ scores exhibited negligible to low responsiveness to improvement in self-perceived effects of heat (SRM:0.08 to 0.25), but changed in unexpected directions to worsening in self-perceived effects of heat. Multivariate random effects models showed that both the onset and conclusion of heatwave were associated with alleviation of certain health and wellbeing problems measured by the EQ-5D-5L and EQ-HWB.

CONCLUSIONS: The EQ-5D-5L, EQ-HWB and EQ-HWB-S demonstrated satisfactory known-groups validity and limited responsiveness in measuring the health and wellbeing impact of heatwaves. EuroQol instruments overall seem potentially useful for heatwave research.