Histology Grade Is Independently Associated With Relapse Risk in Patients With Ulcerative Colitis in Clinical Remission: A Prospective Study.

OBJECTIVES: Objective evidence of inflammation has been associated with the risk of relapse in patients with ulcerative colitis (UC) who are in clinical remission. We compared endoscopic and histologic grades for their ability to predict clinical relapse in this patient population. METHODS: Patients with UC in clinical remission were prospectively enrolled into an observational cohort. Baseline endoscopic scores (Mayo) and histological (Geboes) grades and blood markers were collected. All subjects were followed for 12 months and relapse determined using clinical indices. RESULTS: A total of 179 subjects were enrolled into the study and followed for 12 months. Clinical relapse occurred in 23%; 5% were hospitalized, and 2% underwent colectomy. In univariate analysis, the baseline Mayo endoscopy score and the Geboes histology grade were significantly associated with the later development of clinical relapse (P<0.001 for both), but only the histology grade remained significant in a multivariate model (P=0.006). The relative risk of clinical relapse was 3.5 (95% CI 1.9-6.4, P<0.0001) in subjects whose baseline Geboes grade was ≥3.1. The area under the curve was 0.73 for the Geboes histology grade to identify subjects at risk of future clinical relapse. Of the patients in clinical, endoscopic, and histological remission at baseline (n=82), only 7% had a clinical relapse over the subsequent 12 months. CONCLUSIONS: Histology grade has the strongest association with the risk of clinical relapse in patients with UC who are in clinical remission. Consideration should be given to including this end point in evaluating therapy for UC.