A Rasch model analysis to test the cross-cultural validity of the EuroQoL-5D in the Schizophrenia Outpatient Health Outcomes Study.

Abstract

To investigate the pan-European, cross-cultural validity of the EuroQol-5D (EQ-5D) for assessing quality of life in the Schizophrenia Outpatient Health Outcomes (SOHO) Study. The EQ-5D items investigated were mobility, self-care, usual activities, pain/discomfort and anxiety/depression. A Rasch rating scale model (a form of differential item functioning) was used to identify invariance of item calibrations for the 10 European countries participating in the SOHO study. There was general congruence in the EQ-5D item calibration pattern. The rank of average EQ-5D item calibrations was similar for all countries except Denmark. Denmark showed slight misfits for mobility and pain/discomfort. The EQ-5D is an appropriate measure of health-related quality of life across European countries and translations.