Abstract
BACKGROUND: The EQ-5D-Y-3L is widely used for measuring and valuing HRQoL in paediatric populations. This mixed methods study used the EQ-5D-Y-3L measure and applied a retrospective think-aloud approach to examine the self-report validity in children of varying chronological age. METHODS: A mixed methods study was conducted in a community-based sample of 39 children aged 6-12 years. In a semi-structured interview, children self-completed the EQ-5D-Y-3L and then engaged in retrospective think-aloud. Conversations were audio-recorded and transcribed for analysis in NVivo using the Tourangeau four-stage response model framework to assess comprehension, judgment, recall, and response mapping issues. Fisher's exact test was used to assess the differences between child-self reported HRQoL across subgroups. The inter-rater agreement between child-parent dyads was assessed with CCC for overall HRQoL and Gwet's AC(1) for dimension level HRQoL. RESULTS: Overall, response issues were detected in n = 18 (46%) children. Comprehension issues were apparent in the "having pain or discomfort" dimension where children found it challenging to understand 'discomfort'. Recall-related issues were observed where children's responses were influenced by their typical tendencies (e.g., being usually worried) or past incidences (e.g., feeling pain sometimes). Judgement-related issues were the most common, particularly in the "doing usual activities" dimension, where children tended to respond based on their self-perceived ability to engage in activities rather than health-related limitations. None of the participants were found to have problems with response mapping. A healthy lifestyle that included diet and exercise was a notable consideration in EQ VAS ratings. The younger age groups had a higher proportion of response issues (6-7 years: 64%, 8-10 years: 62%), compared to older children (11-12 years: 20%). Moreover, children with response issues demonstrated significantly lower EQ-5D-Y-3L scores (mean = 0.78, se = 0.04) as compared to those without (mean = 0.95, se = 0.02) (p-value < 0.001). The overall inter-rater agreement was higher for those without any response issues (CCC = 0.33) than those with (CCC = 0.14). Additionally, higher agreement was noted across all the five dimensions in the subgroup with no response issues relative to those with. CONCLUSIONS: Children in the general community may have different perceptions of HRQoL when responding to the EQ-5D-Y-3L possibly due to their limited experience with health-related challenges. The retrospective think-aloud approach adopted highlighted the relatively higher prevalence of response issues in the younger children (ages < 11 years), indicating the need for careful interpretation of self-reported HRQoL using the current version of the EQ-5D-Y-3L in this population.