Defining Endoscopic Remission in Crohn's Disease: MM-SES-CD and SES-CD Thresholds Associated With Low Risk of Disease Progression

Background & Aims: We assessed Modified Multiplier Simple Endoscopic Score for Crohn's Disease (MM-SES-CD) and Simple Endoscopic Score for Crohn's Disease (SES-CD) thresholds that are best associated with low likelihood of long-term disease progression. Methods: Data from 61 patients with early Crohn's disease (CD) who participated in the CALM long-term extension study were used as the derivation cohort and validated using the McMaster inflammatory bowel disease database (n = 99). The primary outcome was disease progression (new internal fistula/abscess, stricture, perianal fistula or abscess, CD-related hospitalization or surgery) since the end of the CALM trial. Optimal MM-SES-CD and SES-CD thresholds were determined using the maximum Youden index. Receiver operating characteristic curve analyses compared threshold scores of remission definitions on disease progression. Results: In the derivation cohort, based on the maximum Youden index, the optimal thresholds associated with a low likelihood of disease progression were MM-SES-CD <22.5 and SES-CD <4. A significantly greater proportion of patients with a MM-SES-CD ≥22.5 had disease progression as compared with patients in the derivation cohort with MM-SES-CD <22.5 (10/17 [58.8%] vs 3/44 [6.8%]; P < .001). Similarly, a significantly greater number of patients with SES-CD ≥ 4 had disease progression compared with those with a SES-CD <4 (11/25 [44.0%] vs 2/36 [5.6%]; P < .001). Compared with other clinical or endoscopic remission definitions, which demonstrated poor to fair accuracy, MM-SES-CD <22.5 performed the best for predicting disease progression (area under the curve = 0.81; 95% confidence interval, 0.68-0.94; P < .001). These thresholds were confirmed in the validation cohort. Conclusion: Achievement of MM-SES-CD <22.5 or SES-CD <4 in patients with ileocolonic or colonic CD is associated with low risk of disease progression and may be suitable targets in clinical trials and practice for endoscopic healing.