Objectives: The EuroQol Group recently released youth (Y) and 5-level (5L) versions of its 3-level EQ-5D instrument (3L) that measures health-related quality of life. In this study, we (1) compare 3L, Y, and 5L responses among US adults and (2) assess construct validity.
Study design and setting: Using a nationally representative sample of US adults (N = 2,619), we collected 3L, Y, and 5L responses in random order and estimated their associations and their relationship with a 0 to 100 numerical visual analog scale.
Results: The prevalence of US adults in the best possible EQ-5D state (i.e., 11111) was lower for the Y (38%) and 5L (35%) than for the 3L (44%), capturing more health problems. However, the prevalence of extreme responses in pain/discomfort and anxiety/depression decreased substantially between the 3L and 5L (from 44% to 17% and from 29% to 13%, respectively).
Conclusion: Compared with the 3L, the Y and 5L versions describe population health as having more, yet milder, health problems. Although the 5L may have advantages in patient populations in which extreme problems are more prevalent, population studies or studies that follow patients from childhood may consider using the Y.
Keywords: EQ-5D; EQ-5D-3L; EQ-5D-5L; EQ-5D-Y; EuroQol; PRO; Patient-reported outcomes.
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