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

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.

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.

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).

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.