The Mayo Endoscopic Subscore (MES) is widely used to assess endoscopic inflammatory activity in ulcerative colitis (UC). More recently, additional indices such as the Modified MES (MMES) and Dublin index have been proposed to improve the prediction of clinical outcomes. However, real-world evidence directly comparing these scoring systems remains limited. Therefore, we evaluated the predictive performance of MES, Modified MES(MMES)⁽¹, and the Dublin index⁽² in patients with clinical remission UC undergoing colonoscopy.

Consecutive patients who had maintained sustained corticosteroid-free remission for at least 6 months, had a partial Mayo score ≤1, and underwent colonoscopy at our institution between August 2022 and February 2023 were prospectively enrolled. .Following index colonoscopy, patients were followed every 8 or 12 weeks for 24 months or until clinical relapse occurred. Clinical relapse was defined as a partial Mayo score >2. The area under the receiver operating characteristic curve (AUC). of each endoscopic index was compared. The sensitivity, specificity, and risk ratio (RR), were also assessed. MMES was calculated by multiplying the sum of MES across five colonic segments (MS) by the maximal evaluated extent of the colon measured in decimetres during withdrawal, and dividing the resulting EMS by the number of segments with MES > 0. The DUBLIN score was calculated as the product of the highest MES (0–3) observed during colonoscopy and disease extent classified according to the Montreal system (E1–E3).

A total of 166 patients were included. Ten patients were lost the follow up. The remaining 156 patients were analysed.  Among them, 21 patients experienced clinical relapse.The AUCs were 0.766, 0.754, and 0.787 for MES, MMES, and the Dublin index, respectively.The best cut-off values for predicting clinical relapse were 1, 4, and 2 for MES, MMES, and the Dublin index, respectively.At the best cut off, the sensitivity, specificity, and relative risk were 0.857, 0.556, and 6.000 for MES; 0.857, 0.474, and 4.517 for MMES; and 0.429, 0.933, and 5.750 for the Dublin index, respectively.

Both the MMES and Dublin index showed no clear advantage over the conventional MES in predicting clinical relapse. Although these indices provide more detailed segmental assessment, they did not yield improved discriminative performance. In this post hoc analysis, the results suggest that the conventional MES may also have potential for predicting relapse risk in routine clinical practice.