OBJECTIVES: To compare the ability of individual and societal preference scores based on the EQ-5D to identify active inflammatory bowel disease (IBD) in Germany. METHODS: Members of the German IBD Association documented Health-Related Quality of Life (hrQoL) with the EQ5-D and other disease-related factors. Inactive or active disease was based on calculated IBD activity indices. Disease activity was also classified (present or absent) according to sick-leave and hospitalizations, documented retrospectively (three months) and prospectively (four weeks). EQ-5D index scores were calculated using British (EQ-5DBT) and German (EQ-5DGT) tariffs. Differences in EQ VAS and EQ-5D index scores between patient groups differing in disease activity, sick-leave and hospitalizations were determined by effect size (ES) and bootstrap test for the standardised difference between the means. ES and bootstrap-test probability are always reported in this consecutive order: EQ VAS, EQ-5DBT and EQ-5DGT. RESULTS: A total of 527 retrospective and 483 prospective questionnaires were analysed. Retrospectively, 20% reported sick-leave, 7% hospitalisation, whereas prospectively, 12% reported sick-leave, 2% hospitalisation. 39% had active disease. All preference scores differed significantly between patients with active and inactive disease (ES: 13.72, 11.47, 9.56; p: 0.0001(all)). Retrospectively, ES of preference scores of patients differing in sick-leave (ES: 4.35, 4.51, 3.37; p: 0.0001, 0.0001, 0.002) and hospitalisation (ES: 2.07, 2.17, 1.91; p: 0.047, 0.047, 0.081) were large. Prospectively, the ES of preference scores for sick-leave groups (ES: 4.34, 4.32, 3.00; p: 0.0001, 0.0002, 0.0119) and hospitalisation (ES: 3.45, 3.08, 2.50; p: 0.014, 0.022, 0.061) were also large. CONCLUSIONS:In German IBD subjects, the ES of all preference scores was large regarding disease-activity, sick-leave and hospitalisation both retrospectively and prospectively. Bootstrap-test probability showed that the EQ-5DGT discriminated less well between the groups than the other preference scores.