An investigation of inter-rater and intra-proxy agreement in measuring quality of life of children in the community using the EQ-5D-Y-3L

Diana Khanna, Jyoti Khadka, Christine Mpundu-Kaambwa, Gang Chen, Kim Dalziel, Nancy Devlin, Julie Ratcliffe, in collaboration with the Quality of Life in Kids: Key Evidence to Strengthen Decisions in Australia (QUOKKA) Project Team

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Background: Self-reporting of health-related quality of life (HRQoL) in children is not always feasible. To date, proxy perspectives (Proxy versions 1 and 2) using the EQ-5D-Y-3L have not been explored for its impact on agreement with child self-report. Proxy version 1 requires the proxy to consider their own view of the child’s HRQoL (proxy-proxy), while with Proxy version 2, the proxy is asked to respond as they believe their child would self-report their HRQoL (proxy-child). This study compared the inter-rater and intra-proxy agreement (overall and dimension level) using the EQ-5D-Y-3L self, proxy-proxy, and proxy-child reports. Methods: A community-based sample of child (aged 6–12 years) and parent dyads were invited to participate in a semi-structured interview. The child self-completed the EQ-5D-Y-3L independently of the parent who completed the EQ-5D-Y-3L from proxy-proxy and proxy-child perspectives. Agreement was determined using Concordance Correlation Coefficients (CCCs) for the overall (preference-weighted) HRQoL, while agreement at the dimension level was evaluated using Gwet’s agreement coefficient (AC1). To assess the differences between the self and the two proxy reports, the Wilcoxon matched-pair signed-rank test was used. Results: This study involved 85 child-parent dyads. The agreement between self and proxy overall HRQoL was low (fair) with both proxy-proxy (CCC = 0.28) and proxy-child (CCC = 0.26) reports. The largest discrepancy in the child-proxy agreement at dimension level with both the proxy versions was observed for ‘feeling worried, sad or unhappy’. Within this dimension, the proxy-child perspective resulted in a stronger agreement (AC1 = 0.7, good) with child self-report compared with the traditional proxy-proxy perspective (AC1 = 0.58, moderate). Although the preference-weighted HRQoL was consistent across both the proxy perspectives, a significant difference was observed in the EQ VAS scores (p = 0.02). Conclusions: This study demonstrates that choice of proxy perspective may have an impact on the problems reported on HRQoL dimensions and EQ VAS scores. However, in this community-based sample of generally healthy children, no significant difference was observed in the inter-rater agreement for child-self and proxy preference-weighted EQ-5D-Y-3L values based on proxy perspectives. While this suggests that preference-weighted data are not sensitive to the choice of perspective, these findings may differ for different HRQoL instruments and for alternative value sets with different properties.

Original languageEnglish
Number of pages16
Publication statusAccepted/In press - 2024

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