What Determines the Shape of an EQ-5D Index Distribution?

Abstract

Background. EQ-5D-3L index scores in patient and general populations typically have a nonnormal distribution, divided into 2 distinct groups. It is important to understand to what extent this is determined by the way that the EQ-5D-3L index is constructed rather than by the true distribution of ill health. Objective. This paper examines the determinants of the "2 groups" distribution pattern and the extent to which this pattern is attributable either to the EQ-5D-3L classification system used to create health state profiles or to the weights applied to profiles. Methods. Data from the English NHS PROMs program (hip and knee replacements and varicose vein and hernia repairs) and from a study ..