Reliability and Responsiveness of Endoscopic Indices for Assessing Crohn’s Disease Postoperative Recurrence in the PREVENT trial

Assessing endoscopic activity is integral in the management of postoperative Crohn's disease (CD). We aimed to comprehensively characterize the reliability and responsiveness of different endoscopic instruments when used to assess postoperative CD activity. Ileocolonoscopy videos (n=70) from the PREVENT trial were reviewed by three blinded central readers. Disease activity was assessed using the Rutgeerts and modified Rutgeerts scores, POCER index, REMIND score, Simple Endoscopic Score for CD (SES-CD), and the CD Endoscopic Index of Severity (CDEIS). Reliability was quantified by the intraclass correlation coefficient (ICC). Responsiveness was quantified using the win probability (WinP) defined as the probability that a patient in the treatment (infliximab) group had a better score than a patient in the placebo group. The neoterminal ileum, anastomosis, and distal colon were scored separately. Inter-rater reliability was substantial for the Rutgeerts and modified Rutgeerts scores, ileal REMIND score, SES-CD, and CDEIS (ICC 0.74-0.80), moderate for the POCER index (ICC 0.49), and fair for the anastomotic REMIND score (ICC 0.30). A large degree of responsiveness was observed for the Rutgeerts and modified Rutgeerts scores, ileal REMIND score, SES-CD, and CDEIS (WinP 0.75-0.83). The degree of responsiveness for the POCER index and the anastomotic REMIND score was small (WinP 0.54 and 0.53, respectively). Estimates of index reliability and responsiveness were consistently lower when assessed at the anastomosis or distal colonic segment compared to the neoterminal ileum. Existing endoscopic indices are reliable and responsive for assessing postoperative CD activity in the neoterminal ileum, although are suboptimal for evaluation in the anastomosis or distal colonic segment.