Impact of Endoscopic and Histologic Activity on Disease Relapse in Ulcerative Colitis

INTRODUCTION: Endoscopic healing is currently considered the main target in the management of ulcerative colitis (UC). There are conflicting data about the role of histology as a stricter treatment objective. We aim at evaluating the additional benefit of histologic remission over endoscopic remission. METHODS: We performed a prospective observational study at the McGill University Health Center. We enrolled adult patients with UC in clinical remission for at least 3 months undergoing a colonoscopy. Endoscopic disease activity was based on the Mayo endoscopic score. Rectal biopsies were obtained, and the histologic activity was evaluated using the Geboes score (active disease defined as Geboes score >= 3.1) with the addition of assessing the presence of basal plasmacytosis. Patients were followed up for 12 months for disease relapse defined as a partial Mayo score of > 2. At the time of relapse or end of follow-up, all patients underwent repeat endoscopic evaluation. The primary end point was clinical relapse. RESULTS: Two hundred fifty-three patients were included. The presence of basal plasmacytosis was associated with relapse (adjusted odd ratio = 2.07, 95% confidence interval [CI] 1.06-4.18, P = 0.042). Time to clinical relapse was significantly higher for patients with Mayo endoscopic score > 0 with adjusted hazard ratio = 2.65, 95% CI 1.31-5.39, and P = 0.007. Time to clinical relapse was not significantly higher for Geboes score >= 3.1 with adjusted hazard ratio = 1.29, 95% CI 0.67-2.49, and P = 0.45. DISCUSSION: Active histologic disease did not affect time to clinical relapse in patients with UC who achieved endoscopic remission while the presence of basal plasmacytosis is associated with relapse.