Inter-observer agreement in endoscopic scoring systems: preliminary report of an ongoing study from the Italian Group for Inflammatory Bowel Disease (IG-IBD)

Abstract

Background: Endoscopic activity has become a therapeutic endpoint in inflammatory bowel disease. Aim of this study was to evaluate inter-observer agreement for endoscopic scores in a real-life setting.

Methods: 14 gastroenterologists with experience in inflammatory bowel disease care and endoscopic scoring reviewed videos of ulcerative colitis (n=13) and postoperative (n=10) and luminal (n=8) Crohn's disease. The Mayo subscore for ulcerative colitis, Rutgeerts score for postoperative Crohn's disease, Crohn's disease endoscopic index of severity (CDEIS), and the simple endoscopic score-Crohn's disease (SES-CD) for luminal Crohn's disease were calculated. A subset of five endoscopic clips were assessed by 30 general gastroenterologists without specific experience in endoscopic scores. Kappa statistics and intraclass correlation coefficients were used to measure agreement.

Results: Mayo subscore agreement was suboptimal: kappas were 0.53 (95% confidence interval 0.47-0.56) and 0.71 (0.67-0.76) for the two groups. Rutgeerts score agreement was fair: kappas were 0.57 (0.51-0.65) and 0.67 (0.60-0.72). Agreements for CDEIS and SES-CD were good: intraclass correlation coefficients for the two groups were 0.83 (0.54-1.00) and 0.67 (0.36-0.97) for CDEIS and 0.93 (0.76-1.00) and 0.68 (0.35-0.97) for SES-CD, respectively.

Conclusion: The reproducibility of endoscopic scores in inflammatory bowel disease remains suboptimal, which could potentially have major effects on therapeutic choices.

Keywords: CDEIS; Endoscopic scores; Interobserver agreement; Mayo endoscopic subscore; Rutgeerts’ score; SES-CD.