Comparison of the three-level and the five-level versions of the EQ-5D.

EQ-5D is a generic instrument to measure health-related quality of life. In 2009, a new version, EQ-5D-5L, was introduced as an attempt to reduce ceiling effects and improve sensitivity to small changes over time. The objective of this study was to assess the measurement properties of the EQ-5D-5L instrument compared to the EQ-5D-3L instrument in an elderly general population with a moderate to a high degree of comorbidity. A subgroup of participants in a large clinical trial completed the EQ-5D-3L and the EQ-5D-5L questionnaires. Based on the collected data, we tested for feasibility and ceiling and floor effects. Furthermore, we assessed the redistribution properties of the responses and examined the level of inconsistency, informativity, and convergent validity. A total of 1002 persons diagnosed with hypertension, diabetes, heart failure, and/or previous stroke completed both the EQ-5D-3L and the EQ-5D-5L questionnaires. The overall ceiling effect decreased from 46% with the EQ-5D-3L to 30% with the EQ-5D-5L and absolute and relative informativity were higher for EQ-5D-5L, and there was a stronger correlation between EQ-5D-5L and EQ VAS. The EQ-5D-5L seemed to perform better than the EQ-5D-3L in terms of feasibility, ceiling effect, discriminatory power, and convergent validity. The overall ceiling effect was higher than that found in patient samples in previous studies but lower than the one found in population studies.