LAUSR

BACKGROUND Endoscopic and histologic remission have emerged as key therapeutic goals in the management of inflammatory bowel diseases (IBD) that are associated with favorable long-term disease outcomes. Here, we prospectively compared the predictive value of barrier healing with endoscopic and histologic remission for predicting long-term disease behaviour in a large cohort of IBD patients in clinical remission. METHODS At baseline, IBD patients in clinical remission underwent ileocolonoscopy with assessment of intestinal barrier function by confocal endomicroscopy. Endoscopic and histologic disease activity as well as barrier healing were prospectively assessed along established scores. During subsequent follow-up (FU), patients were closely monitored for clinical disease activity and the occurrence of major adverse outcomes (MAO): disease flares, IBD-related hospitalization or surgery, initiation or dose escalation of systemic steroids, immunosuppressants, small molecules or biological therapy. RESULTS 181 patients (100 CD, 81 UC) were included for final analysis. During a mean FU of 35 (CD) and 25 (UC) months, 73% of CD and 69% of UC patients experienced at least one MAO. The probability of MAO-free survival was significantly higher in IBD patients with endoscopic remission compared to endoscopically active disease. In addition, histologic remission predicted MAO-free survival in patients with UC but not in CD. Barrier healing on endomicroscopy was superior to endoscopic and histologic remission for predicting MAO-free survival in both, UC and CD. CONCLUSIONS Barrier healing is associated with decreased risk of disease progression in clinically remittent IBD patients with superior predictive performance compared to endoscopic and histologic remission. Analysis of barrier function might be considered as a future treatment target in clinical trials.