Implications of Value Set Choice on EQ-5D-Y-3L Child and Proxy Health-Related Quality of Life Ratings: What to Do When a Country-Specific “Y” Value Set Is Unavailable?

Objectives: There is limited guidance on whether to apply an available EQ-5D-Y-3L “Y” value set from another country or use a country-specific EQ-5D-3L “adult” value set when a country-specific “Y” value set is unavailable. This study aims to examine how the choice of value set (ie, “Y” or “adult”) influences the interrater gap between child-self and proxy-reported health-related quality of life (HRQoL). 

Methods: An online sample of 845 dyads (children aged 6-10 years and parents) independently completed the self and proxy versions of the EQ-5D-Y-3L. Corresponding HRQoL values were derived using the “Y” and the “adult” value sets for 5 countries: Germany, Hungary, Japan, The Netherlands, and Spain. Analyses were stratified by age (6-7 vs 8-10-year-olds), gender (boys vs girls), and health condition (no vs yes). Group differences were identified using paired t tests. The percentage of directional consistency in child-proxy discrepancies across value sets was also examined as a secondary analysis. 

Results: Proxies significantly overestimated HRQoL values across most “Y” value sets (Hungary, Japan, and Spain). Significant discrepancies using the corresponding “adult” value sets were observed only for Germany. Additionally, significant interrater differences were observed for children without health conditions across all value sets. Proportional agreement in direction was marginally higher when using “Y” value sets, except for Germany. 

Conclusions: The choice of value set influences child-proxy HRQoL assessments. In the absence of a country-specific “Y” value set, using an alternative “Y” value set is preferable to relying solely on a country-specific “adult” value set.