P0315 Incidence and risk factors for disease progression in patients with ulcerative proctitis: a retrospective cohort study
Authors: Pierik R J , Derikx L A A P , Hoekstra J , Post R A J , van Dongen R E A , de Vries A C , Bodelier A G L 
Published: January 2025

Abstract

Background
Ulcerative proctitis (UP) is associated with disabling symptoms including diarrhea, hematochezia and bowel urgency1. Adequate therapy is crucial for symptom control and may reduce the risk of proximal disease extension. Although prior studies have explored risk factors for disease progression, they are limited by small sample sizes and have conflicting results2,3. Therefore, the aim of this study was (1) to assess the incidence and (2) to identify risk factors for disease progression in newly diagnosed UP patients.

Methods
All patients diagnosed with UP (inflammation ≤15 cm beyond the anal verge) between January 2000 and January 2024 in one large, non-academic hospital (Amphia Hospital, Breda, The Netherlands) were included in this retrospective cohort study. Data were collected from diagnosis to the end of follow-up. Disease progression was defined as UP (Montreal E1) endoscopically progressing to left-sided (E2) or pancolitis (E3). The Fine & Gray (F&G) regression model was used to identify risk factors for disease progression. 1-, 5- and 10-year progression rates were extracted, adjusted for the competing event of prolonged remission4.

Results
In total, 265 UP patients were included; 158 (60%) were female and median age at diagnosis was 40 years. 189 patients (71%) reached clinical remission with topical and/or oral 5-aminosalicylates (5-ASA) and/or topical steroids; 133 (50%) required only topical and/or oral 5-ASA. During a median follow-up of 5.4 years (IQR 2.0-10.8), disease progression occurred in 54 patients (20%), of whom 38 (14%) progressed to E2 and 16 (6.0%) to E3. Median time to progression was 45 months (IQR 18-104). The cumulative incidence of disease progression was 3.2% (95% CI 2.9-3.5%) at 1 year, 15.4% (95% CI 14.3-16.5%) at 5 years and 23.2% (95% CI 21.1-25.4%) at 10 years after diagnosis and would have been overestimated with a traditional survival analysis (Figure 1). F&G analyses demonstrated that age &lt;18 years at diagnosis (HR 3.29, [95% CI 1.44–7.52], p=0.005) and steroid-free remission at 3 months (HR 0.46, [95% CI 0.23–0.91], p=0.025) were significant predictors for disease progression (Table 1).

Conclusion
In this large cohort of newly diagnosed UP patients, the 10-year cumulative incidence of disease progression was 23.2%. Although most patients responded well to conventional treatment, 29% required immunosuppressants and/or advanced therapies. Steroid-free remission at 3 months and age &lt;18 at diagnosis were significant predictors for disease progression. Awareness of these predictors could help identify high-risk patients who may benefit from tailored monitoring strategies, as well as low-risk patients that may be suitable for referral back to primary care.

References
1.Meucci G, Vecchi M, Astegiano M, et al. The natural history of ulcerative proctitis: a multicenter, retrospective study. Gruppo di Studio per le Malattie Infiammatorie Intestinali (GSMII). Am J Gastroenterol. 2000;95(2):469-473.
2.Huguet JM, Ferrer-Barceló L, Suárez P, et al. Endoscopic progression of ulcerative proctitis to proximal disease. Can we identify predictors of progression?. Scand J Gastroenterol. 2018;53(10-11):1286-1290.
3.Walsh E, Chah YW, Chin SM, et al. Clinical Predictors and Natural History of Disease Extension in Patients with Ulcerative Proctitis. Inflamm Bowel Dis. 2017;23(11):2035-2041.
4.Andersen PK, Geskus RB, de Witte T, Putter H. Competing risks in epidemiology: possibilities and pitfalls. Int J Epidemiol. 2012;41(3):861-870.