Histological inflammatory activity can predict endoscopic relapse in patients with ulcerative colitis who have achieved mucosal healing.

BACKGROUND AIMS Current therapeutic goals in ulcerative colitis (UC) include clinical and endoscopic remission, named mucosal healing (MH). Despite MH, a proportion of patients suffer a clinical relapse, which has been related to histological inflammation. We aimed to identify which histopathological features or histopathological index cut-off was associated with endoscopic relapse (ER) in UC patients with MH. METHODS Retrospective analysis of UC patients who underwent surveillance colonoscopy showing complete MH (endoscopic Mayo subscore=0) with random biopsies, and at least one more endoscopy along the follow-up. After a consensus meeting, expert pathologist performed histological assessment according to Simplified Geboes Score (SGS), Nancy Index (NI) and Robarts Histopathological Index (RHI). Other histopathological features were also evaluated. Patients were followed until ER or last endoscopy performed showing persistence of MH. RESULTS A total of 95 patients (150 colonoscopies) were included. After mean follow-up of 31.2 months (SD 21.7), 33 patients (34.7%) suffered ER. Neutrophils in lamina propria (OR 2.6; P = 0.037), within the epithelium (OR 2.6; P = 0.03), SGS ≥3.1 (OR 2.6; P = 0.037), NI ≥2 (OR 2.6; P = 0.03) and RHI ≥5 (OR 2.6; P = 0.037) were associated with ER in univariate analysis. In multivariate analysis, eosinophils in the lamina propria (HR 2.5; P = 0.01) and clinical remission<12 months (HR 3.2; P = 0.002) were associated with ER. CONCLUSIONS Histopathological findings in UC patients who have achieved endoscopic MH may predict ER. Standardized histopathology reports according to the presence of neutrophils, eosinophils or to defined cut-off of validated histopathologic indexes may represent a useful tool to predict ER and should be considered at therapeutic and surveillance decision process.