Histological scoring plays a key role in the assessment of disease activity in ulcerative colitis (UC) and is also important in Crohn´s disease (CD). Currently, there is no common scoring available for UC and CD. We aimed to validate the Inflammatory Bowel Disease (IBD) – Distribution (D), Chronicity (C), Activity (A) score (IBD-DCA score) for histological disease activity assessment in IBD.
Inter- and intra-rater reliability were assessed by 16 observers on biopsy specimen from 59 patients with UC and 25 patients with CD. Construct validity and responsiveness to treatment were retrospectively evaluated on a second cohort of 30 patients.
Inter-rater reliability was moderate to good for the UC cohort (intraclass correlation coefficients (ICCs) = 0.645, 0.623, 0.767 for D, C and A, respectively) and at best moderate for the CD cohort (ICC = 0.690, 0.303, 0.733 for D, C and A, respectively). Intra-rater agreement ranged from good to excellent in both cohorts. Correlation with the Nancy Histological Index (NHI) was moderate and strong with the Simplified Geboes Score (SGS) and a Visual Analog Scale (VAS). Large effect sizes (ES) were obtained for all three parameters. External responsiveness analysis revealed correlated changes between IBD-DCA score and NHI, SGS and VAS.
The IBD-DCA score is a simple histological activity score for UC and CD, agreed and validated by a large group of IBD specialists. It provides reliable information on treatment response. Therefore, it has potential value for use in routine diagnostics as well as clinical studies.

© The Author(s) 2021. Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation.

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