Residual Short-Segment Distal Inflammation Has No Significant Impact on the Major Relapse of Extensive Ulcerative Colitis

Background: Mucosal healing is a treatment target for patients with ulcerative colitis. However, the relevance of proactive treatment for residual inflammation limited to the distal colon is unclear. Materials and Methods: Patients with ulcerative colitis who had extensive colitis in clinical remission and underwent colonoscopy were retrospectively enrolled and followed up for 2 years. Patients with complete endoscopic remission (CER; Mayo endoscopic subscore [MES] of 0) and those with short-segment distal inflammation (SS; active inflammation only in the sigmoid colon and/or rectum with a proximal MES of 0) were compared for the incidence of minor (only symptomatic) and major (need for induction treatments or hospitalization) relapses. Results: A total of 91 patients with CER and 54 patients with SS were identified and 63 relapses (47 minor and 16 major) were analyzed. Univariate analysis showed that minor relapses were significantly more frequent in the SS group than in the CER group (hazard ratio [HR], 2.22; 95% confidence interval [CI], 1.25-3.97), but major relapses were not more frequent in the SS group than in the CER group (HR, 1.78; 95% CI, 0.65-4.83). Multivariable analysis showed that SS was the only risk factor significantly associated with minor relapse (HR, 2.38; 95% CI, 1.31-4.36). When the SS group was stratified by MES of 1 vs 2/3, minor relapses were significantly more frequent in the subgroup with MES of 2/3 than in the CER group, whereas the incidence of major relapse remained similar. Conclusions: Residual short-segment distal inflammation is not a risk factor for major relapses as long as endoscopic remission is achieved in the proximal colon. Therefore, reactive but not proactive treatment may be appropriate for such lesions.