Histologic Activity and Steroid Use History Are Risk Factors of Clinical Relapse in Ulcerative Colitis with Mayo Endoscopic Subscore of 0 or 1

Background: The treatment goal of ulcerative colitis (UC) has changed from the control of symptoms to mucosal healing, previously evaluated mainly by endoscopy. Recently, the importance of histologic activity has emerged. Therefore, this study aimed to investigate the risk of clinical relapse according to histologic activity in UC with a Mayo endoscopic subsccore (MES) of 0 or 1. Methods: In a retrospective cohort after our center’s biopsy guideline for UC was instituted, 492 UC patients with an MES of 0 or 1 were enrolled and analyzed. The primary outcome was the development of a clinical relapse including changes in medication, hospitalization, colectomy, and the development of colorectal cancer during the follow-up period. Results: During the median 549 days of follow-up, 92 (18.7%) patients had a clinical relapse. All the patients changed their medication, including 4 hospitalized patients. Histologic activity defined by a Geboes score of ≧3.1 (hazard ratio [HR], 1.732; P = .035) and steroid use history (HR, 1.762; P = .008) were independent factors associated with clinical relapse. When stratified, the 1- and 2-year incidence rates of clinical relapse were 4.1% and 10.6%, respectively, for patients with histologic improvement and no steroid use history, whereas the rates were 23.9% and 39.4% for patients with histologic activity and steroid use history. Conclusions: In UC with an MES of 0 or 1, histologic activity and steroid use history can be used to stratify the risk of clinical relapse.