Categorising Endoscopic Severity of Crohn's Disease Using the Modified Multiplier SES-CD [MM-SES-CD]

Background and Aims: Current endoscopic scoring indices such as the Simple Endoscopic Score for Crohn's Disease [SES-CD] quantify the degree of mucosal inflammation in Crohn's disease [CD] but lack prognostic potential. The Modified Multiplier of the SES-CD [MM-SES-CD] quantifies the endoscopic burden of CD and can be accessed online [https://www.mcmasteribd.com/mm-ses-cd]. This analysis aims to establish MM-SES-CD thresholds that classify CD endoscopic burden into inactive/very mild, mild, moderate, and severe disease based on the probability of achieving endoscopic remission [ER] on active therapy at 1 year. Methods: This post-hoc analysis included pooled data from three CD clinical trials [n = 350 patients, baseline SES-CD ≥3 with ulceration]. Disease category severity was determined using the maximum Youden Index. Achievement of ER between severity categories was compared using chi square tests. Time to clinical remission [CR] was compared using Kaplan-Meier survival curves. Results: MM-SES-CD severity categories were established as very mild/remission [score <14], mild [≥14 to <31], moderate [≥31 to <45], and severe [≥45], which were predictive of 1-year ER [50%, 30.3%, 21.7%, 8.8%, respectively, p <0.001]. Lower MM-SES-CD scores had numerically higher rates of 1-year clinical remission [CR], and time to 1-year CR was superior to those with higher scores [p = 0.0492]. MM-SES-CD thresholds for achieving 1-year ileal ER among 75 patients with isolated ileal disease were established as mild [score <14], moderate [≥14 to <33], and severe [≥33], which were predictive of 1-year ER [66.7%, 33.3%, 13.3%, respectively, p = 0.027]. Conclusions: We have established numerical MM-SES-CD cut-offs that categorise endoscopic disease severity and have demonstrated that they are prognostic for 1-year ER and CR.