Clinical characteristics and prognosis of patients with ulcerative colitis that shows rectal sparing at initial diagnosis

BACKGROUND: Ulcerative colitis (UC) is characterised by mucosal inflammation from the rectum to its proximal area in a symmetric and continuous fashion. However, although uncommon, we encounter cases of UC with rectal sparing in the initial stage. AIM: To evaluate the clinical characteristics and clinical course for rectal sparing UC compared with typical UC. METHODS: We looked at records from 2004 to 2015, and selected patients who were newly diagnosed with UC, and who could be followed up for at least 5 years in our hospital. We then retrospectively analysed the medical records and endoscopic findings of those patients. To compare the clinical course and prognosis, we matched each patient with rectal sparing UC 1:3 with controls by age, sex, and disease extent. RESULTS: Of 619 UC patients, 24 (3.9%) showed rectal sparing at diagnosis. During the follow-up period (median 8 years), in two (8.3%) of the 24 patients, rectal sparing remained through follow-up inspections; but for the other 22 (91.7%) patients, obvious rectal inflammation was found at follow-up endoscopy. Of the 24 patients, 8 (33.3%) were initially misdiagnosed with infectious colitis. No diagnosis was changed to Crohn’s disease. The uses of corticosteroid or biologic agents, hospitalisation rate, and colectomy rates were not different between the rectal sparing UC group and typical UC group. CONCLUSION: Some patients with UC can reveal atypical patterns of disease distribution, such as rectal sparing in its initial stage; but despite this, the clinical course and prognosis may not differ from those of typical UC patients.