Validity of the EQ–5D–5L and reference norms for the Spanish population

Background and objective: The EuroQol 5 dimensions 5 levels (EQ–5D–5L) is the new version of EQ–5D, developed to improve its discriminatory capacity. This study aims to evaluate the construct validity of the Spanish version and provide index and dimension population-based reference norms for the new EQ–5D–5L. Methods: Data were obtained from the 2011/2012 Spanish National Health Survey, with a representative sample (n = 20,587) of non-institutionalized Spanish adults (≥ 18 years). The EQ–5D–5L index was calculated by using the Spanish value set. Construct validity was evaluated by comparing known groups with estimators obtained through regression models, adjusted by age and gender. Sampling weights were applied to restore the representativeness of the sample and to calculate the norms stratified by gender and age groups. We calculated the percentages and standard errors of dimensions, and the deciles, percentiles 5 and 95, means, and 95% confidence intervals of the health index. Results: All the hypotheses established a priori for known groups were confirmed (P < 0.001). The EQ–5D–5L index indicated worse health in groups with lower education level (from 0.94 to 0.87), higher number of chronic conditions (0.96–0.79), probable psychiatric disorder (0.94 vs 0.80), strong limitations (0.96–0.46), higher number of days of restriction (0.93–0.64) or confinement to bed (0.92–0.49), and hospitalized in the previous 12 months (0.92 vs 0.81). Conclusions: The EQ–5D–5L is a valid instrument to measure perceived health in the Spanish-speaking population. The representative population-based norms provided here will help improve the interpretation of results obtained with the new EQ–5D–5L.