Interobserver variability of endoscopic scores and their subsections in Crohn�s Disease: a single-center prospective study

BACKGROUND AND AIMS: accurate endoscopic assessment is crucial for treatment decisions in Crohn's disease (CD), but endoscopic scores are complex and not easily applicable in routine practice. This study aimed to assess interobserver reproducibility of Crohn's Disease Endoscopic Index of Severity (CDEIS), Simple Endoscopic Score for Crohn's Disease (SES-CD) and their subsections, in inflammatory bowel disease (IBD) experts and non-experts, to improve endoscopic assessment. METHODS: an observational, prospective study was performed including 22 CD patients who underwent routine colonoscopy at an IBD unit, after excluding patients with inadequate bowel preparation (Boston Bowel Preparation score < 6). Seven endoscopists from four centers, four specialized in IBD, independently scored the videos using CDEIS and SES-CD. Interobserver variability was assessed, comparing IBD experts and non-experts, and correlating endoscopic scores with clinical activity and biomarkers. RESULTS: overall intra-class correlation coefficient (ICC) was 0.83 for CDEIS and 0.77 for SES-CD, indicating substantial agreement. The lowest correlations were found with deep ulcers in the ileum, descending colon, and rectum (CDEIS), and ulcer size in the ileum and stricture detection in the descending colon (SES-CD). Non-IBD experts showed higher interobserver agreement (ICC: 0.91 CDEIS, 0.88 SES-CD) compared to IBD experts (ICC: 0.79 for both). No correlation was found between endoscopic scores and Harvey-Bradshaw index or C-reactive protein (CRP). SES-CD showed a significant correlation with fecal calprotectin (0.58, p = 0.01) and CDEIS trended towards significance (r = 0.44, p = 0.064). Regarding endoscopic remission, 22 % patients were inconsistently classified. CONCLUSIONS: although CDEIS and SES-CD are highly reproducible without specialized training, they have limitations to detect mild inflammatory activity. An ideal score should emphasize ileal activity and simplify the assessment of ulceration severity and stenosis to improve clinical utility.