Natural History and Longitudinal Outcomes of Patients with Mild-to-Moderate Ulcerative Proctitis or Ulcerative Proctosigmoiditis: A Single-Center, Retrospective Study.

Background: Ulcerative proctitis (UP) and ulcerative proctosigmoiditis (UPS) are special forms of ulcerative colitis. The disease burdens of UP and UPS are increasing. However, the natural history and prognosis of patients with mild-to-moderate UP or UPS have been poorly studied.

Aims: The aim of this study is to evaluate the characteristics, short-term and long-term outcomes of patients with mild-to-moderate UP or UPS followed at a single center over a period of 3 years.

Methods: A retrospective study of patients with UP and UPS followed at a single center from 2021 to 2023 was performed. After scanning for inclusion and exclusion criteria, patient demographics and clinical data were collected. Disease severity was accessed by Myao endoscopy scores and ulcerative colitis endoscopic index of severity. Endoscopic improvement was defined as decreased scores at the last follow-up. Disease extension was defined as endoscopic evidence of a greater extent of disease at the last follow-up.

Results: A total of 414 patients were included for evaluation, of which 292 patients (70.53%) were at mild disease stage, and 122 patients (29.47%) had moderate diseases. At the last follow-up, 315 patients (76.09%) showed endoscopic improvement, and 247 patients (59.66%) showed endoscopic remission. An overall extension rate of 11.11% was observed at the last follow-up. Subgroup analysis revealed a better prognosis in younger patients. The disease extension rate was higher in moderate group and symptomatic patients.

Conclusion: Promising outcomes were observed in patients with mild-to-moderate ulcerative proctitis or ulcerative proctosigmoiditis. Disease severity and symptoms are correlated with the risk of extension.