Abstract
BACKGROUND AND AIMS: To determine how the health state of ulcerative colitis patients is impacted by their disease, different health state questionnaires are deployed. This study examines to what extent these health state questionnaires determine the same underlying health state concept and to what extent the complementary use of the health state questionnaires has added value for physicians. METHODS: In total, 307 patients were enrolled in this cross-sectional multicenter cohort study. Medical, psychological, economic, and composite health state questionnaires were administered to determine reliability, convergent validity, and explained variance. Reliability was determined using Cronbach's alpha. Convergent validity was measured using Spearman's correlation coefficients. Explained variance was interpreted using R-squared coefficients. RESULTS: All questionnaires can be considered reliable. The medical, psychological, and economic health state questionnaires show weak to moderate convergent validity with each other. The medical, psychological, and economic health state questionnaires also explain limited variance in each other's outcomes. The composite health state questionnaire shows moderate to strong convergent validity with the other health state questionnaires. The composite health state questionnaire further explains considerable variance in the outcomes of the other health state questionnaires. CONCLUSION: Deploying divergent medical, psychological, and economic health state questionnaires may have added value as they provide a multiperspective holistic insight into patients' health states. Deploying the composite health state questionnaire combined with other health state questionnaires may have added value as it provides additional understanding of their outcomes. Deploying an independent psychological health state questionnaire may have added value as it shows particularly limited convergent validity and explained variance regarding other health state questionnaires.