The psychometric performance of the EQ-5D-5L composite and component items in the U.S. General population and by age group

Abstract

Objectives EQ-5D-5L items, self-care (SC), pain/discomfort (PD), and anxiety/depression (AD), are composites of two components. While PD (comprised of pain [PN] and discomfort [DI]) and AD (comprised of anxiety [AN] and depression [DE]) have been extensively studied, SC (comprised of washing self [WA] and dressing self [DR]) remains underexplored. Additionally, to our knowledge, the psychometric performance of composites versus components has never been investigated across age groups. This study examines the three composites and six components overall and by age group. Methods In 2024, a representative sample of 6,018 US adults participated in an online survey that included the EQ-5D-5L and its six components in fixed order. In the overall sample and separately across age groups (18–29, 30–39, 40–49, 50–59, 60–69, 70+), we evaluated underreporting, ceilings and floors, agreement (weighted Kappa), convergent validity, informativity, explanatory power for EQ VAS (R²), and structural validity (exploratory factor analysis [EFA]). Results The ceiling was lower across all three composites compared to their component items. Strong agreement was found between composites and their corresponding component items (SC: 0.78, PD: 0.91, AD: 0.92). Using component items instead of composites increased the informativity and adjusted R² values. The first-listed components showed stronger convergent validity with their composites. EFA identified three factors: physical functioning (including MO, UA, SC), PD, and AD. Splitting the AD for younger and PD for older populations showed the greatest added value while there were minimal differences between SC and the module of washing and dressing self. Conclusions The EQ-5D-5L composites effectively captured the information provided by their individual components, but replacing PD and AD with their components may improve instrument performance and its adaptability across health concerns relevant to different age groups.