Abstract
PURPOSE: This cross-sectional study aims to understand the relationship between responses on the Anxiety/Depression (A/D) dimension of the EQ-5D-5L and symptoms of anxiety and depression on the GAD-7 and PHQ-9 instruments. In doing so, we investigate the comparative performance of the dimension between diagnostic groups (i.e. anxiety (GAD-7); depression (PHQ-9); anxiety & depression versus none). We additionally investigate the discriminatory performance between sub-populations based on gender, age, education and self-reported chronic conditions. METHODS: 19,902 general population participants completed a health survey in May/June 2020, from five European countries and the United States. Performance of A/D was calculated using the Area Under the Receiver Operating Characteristic curve (AUROC), and was compared to having anxiety (GAD-7 ≥ 8), depression (PHQ-9 ≥ 10) and both versus none for the total population and sub-populations. Several additional sensitivity analyses were conducted, including calculations of the optimal A/D cut-off. RESULTS: The performance in the total sample was good (AUROC > 0.8) and did not differ significantly between diagnostic groups. The performance differed significantly between the age groups, with worse performance in the younger groups, and differed between those with a singular chronic condition, with worse performance in those indicating having an anxiety or depression disorder. The performance did not differ significantly by gender, education, nor total chronic conditions. CONCLUSION: The A/D dimension captures symptoms of anxiety, depression or both equally well. Performance is worse in the younger population. Interpretation in those with a self-reported anxiety or depression disorder should be further investigated. This is the first-of-its-kind large population sample performance analysis, where we present evidence that the performance of the A/D dimension differs between ages, and thus intra-age comparative results may be flawed.