Utility of the Serum-Based Endoscopic Healing Index in Monitoring Therapeutic Response in Ulcerative Colitis

Abstract

INTRODUCTION: Convenient and objective noninvasive tools to monitor therapy response in patients with ulcerative colitis (UC) are needed. This study aimed to evaluate the performance of the Endoscopic Healing Index [EHI], a serum test originally developed to monitor mucosal inflammation in Crohn's disease, in patients with UC. METHODS: Serum samples paired with endoscopic data from consecutive adult patients with UC initiating advanced therapy for active disease (Mayo Endoscopic Subscore [MES] > 1) were analyzed. EHI values were compared between groups showing endoscopic improvement, remission, and nonresponse, defined, respectively, as MES of ≤1, 0 and >1. We also assessed the association of EHI with longitudinal changes of MES and compared its performance with that of fecal calprotectin (FC) and C-reactive protein. RESULTS: A total of 127 patients provided 303 samples. Median EHI increased significantly with increasing MES score (P < 0.001). Median EHI was significantly lower in patients with endoscopic remission or improvement compared with patients with no response (P < 0.001, P < 0.001, respectively). A 10-point decrease in EHI was associated with 89% higher odds of 1-point decrease in MES (P < 0.001). EHI detected MES 0–1 with an area under the receiver operating curve of 77.8%, which was comparable with that of FC and C-reactive protein (85.0% [P = 0.076] and 70.6% [P = 0.055], respectively). DISCUSSION: EHI values are significantly responsive to changes in mucosal inflammation, also in patients with UC, and can confirm and/or rule out mucosal inflammation with an almost similar accuracy to that of FC.