Construct Validity and Responsiveness of EQ-5D-3L in Patients With Rheumatic Disease

In the study, the validity and responsiveness of EQ-5D-3L will be assessed. The EQ-5D-3L measures HRQoL and consists of two parts. The first part contains five questions about mobility, daily activities, self-care, pain/discomfort, and anxiety/depression (EuroQoL 1990, Brooks 1996). Each question can be answered with no problem (1), some/moderate problem (2) unable to perform certain activities/having extreme problems (3). The answers can be summarized in an index value based on an existing preference-based value set. In this study, the EQ-5D-3L value set by Dolan (Dolan 1997) will be used for the main analyses and a Swedish experience-based value set in a sensitivity analysis (Burström, Sun et al. 2014). For the EQ-5D-3L index, 1 represents full health and 0 represents a value equal to being dead. EQ VAS measures the persons health today on a visual analogue scale (VAS) from 0 (worst imaginable health) to 100 (best imaginable health) (EuroQoL 1990, Brooks 1996).