OBJECTIVES: This study evaluates the performance of the EQ-5D-Y in children and young people (CYP) with mental health conditions, using specific phobias as a case study. The aims are to investigate the internal structure of the self-completed EQ-5D-Y-3L and to assess its psychometric performance and explanatory power compared to the CHU-9D.

METHODS: Data were retrieved from the Alleviating Specific Phobias Experienced by Children Trial (ASPECT) (n=267), the first trial study measuring health-related quality of life for full range of specific phobias. Self-reported measures included EQ-5D-Y, CHU-9D, Revised Children’s Anxiety and Depression Scale-Children/Parents (RCADS-C/P); while clinical outcome measures comprises subjective units of distress (SUDS) and anxiety disorder interview schedule (ADIS). Where possible, both the EQ-5D-Y descriptive profile and its utility score (Dutch-Y value set) were analyzed.

RESULTS: Regarding internal structure, the internal model, incorporating mobility, self-care as formative indicators, and pain/discomfort, worried/sad/unhappy, and usual activities as reflective indicators, exhibited a good fit. EQ-5D-Y items correlated well with expected items of CHU-9D, while utility scores of both measures correlated strongly with RCADS-C/P (> 0.5) and weakly correlated with clinical outcomes. In known group analysis, both EQ-5D-Y and CHU-9D demonstrated strong effect-sizes (ES) across RCADS-C/P (ES: 0.9-1.7), and small ES of 0.2-0.4 across SUDS and ADIS subgroups. Defined by RCADS-C/P change, both EQ-5D-Y and CHU-9D exhibited good responsiveness, with CHU-9D showing a larger ES (0.90) than EQ-5D-Y (0.68). For explanatory power, while both measures explained 34% and 54% of variance in RCADS-C scores, respectively, neither EQ-5D-Y nor CHU-9D explain the variance in ADIS or SUDS scores.

CONCLUSIONS: This study is the first comprehensive analysis of the performance of self-complete EQ-5D-Y in CYP with specific phobias. Our study found that both EQ-5D-Y and CHU-9D align more closely with the construct assessed by RCADS-C/P than by other clinical indicators, such as AIDS and USDS.