Validation and Investigation of the Operating Characteristics of the Ulcerative Colitis Endoscopic Index of Severity

BACKGROUND: The Ulcerative Colitis Endoscopic Index of Severity (UCEIS) is a novel instrument to evaluate endoscopic disease activity. It has been demonstrated to outperform the more widely used Mayo endoscopic score (MES) in predicting long-term prognosis, including the need for colectomy. Despite its potential benefits, many clinicians still prefer to use MES because its operating characteristics are better defined and its grades are more readily applicable to clinical decision-making. The aims of our study were to quantify the UCEIS cutoff most closely associated with the need for treatment escalation and to perform a validation exercise using MES and clinical, biochemical, and histological measures of disease activity. METHODS: Endoscopies performed in UC patients between November 2016 and January 2018 were retrospectively reviewed. Agreement between the UCEIS and MES was quantified using Kappa (κ) statistics. A UCEIS cutoff for treatment escalation was calculated using chi-square, receiver operating characteristic curve, and area under the curve (AUC) analyses. The Pearson correlation coefficient was used to compare linear relationships between UCEIS and clinical (Simple Clinical Colitis Activity Index [SCCAI]), biochemical (C-reactive protein [CRP]), and histological (Nancy Histological Index [NHI]) activity. RESULTS: Two hundred one (56%) procedures documented both UCEIS and MES, demonstrating substantial agreement (κ = 0.713; P < 0.001). Treatment was escalated after 199 (56%) procedures. Receiver operating characteristic curve analysis of need for treatment escalation showed the highest sensitivity and specificity for UCEIS ≥4 (0.80 and 0.93, respectively; AUC, 0.93). Of 170 patients with a UCEIS ≥4, treatment was escalated in 159 (94%), but not for 11 (6%). Of 185 patients with a UCEIS ≤3, 40 (22%) were escalated, whereas 145 (78%) were not (P < 0.001). UCEIS correlated strongly with NHI (0.723; P < 0.001), moderately with SCCAI (0.671; P < 0.001), and weakly with CRP (0.279; P < 0.001). CONCLUSIONS: A UCEIS ≥4 was significantly associated with treatment escalation. This cutoff could therefore be used to support clinical decision-making based on endoscopic findings. Strong and moderate correlations were found between UCEIS and histological and clinical disease activity, respectively, whereas a weak correlation was found with CRP. 10.1093/ibd/izy325_Video_1 izy325.video1 5849933952001.