Risk factors and long-term prognosis for colorectal strictures in ulcerative colitis

BACKGROUND Strictures in ulcerative colitis (UC) are relatively uncommon but are associated with increased risk of malignancy and complications. Until recently, fibrogenesis and strictures have remained largely unexplored in UC. AIM To investigate the incidence, long-term prognosis and risk factors of colorectal strictures in a large cohort of UC patients. METHODS A total of 938 hospitalized UC patients at Peking Union Medical College Hospital were included from 2014 to 2024. Stricture was defined as a fixed localized narrowing of the colorectal lumen. Risk factors for stricture formation were identified by multivariable Cox regression. Prognosis was analyzed using the Kaplan-Meier or Fine-Gray method. Sensitivity analysis excluded malignant strictures due to their distinct pathophysiology. RESULTS The overall incidence of stricture was 12.4% over a median follow-up of 8.70 years, with a 10-year cumulative probability of 11.3%. Malignancy occurred in 8.6% of stricture cases. UC patients with strictures were at higher risk for intestinal complications, surgery and malignancy (P < 0.05). The 10-year cumulative probabilities of surgery and all-cause mortality were 37.6% and 1.6%, respectively. Age ≥ 40 years at diagnosis hazard ratio (HR) = 2.197, 95% confidence interval (CI): 1.487-3.242 and extraintestinal manifestations (HR = 2.072, 95%CI: 1.326-3.239) were associated with higher stricture risk, while the use of biological agents such as vedolizumab (HR = 0.382, 95%CI: 0.203-0.720) was protective against strictures (P < 0.05). Sensitivity analysis on benign strictures showed consistent findings, with similar risk factors and worse long-term outcomes. CONCLUSION UC patients with strictures had worse long-term prognostic outcomes. Earlier endoscopic surveillance and biologic treatment should be considered in patients ≥ 40 years or those with extraintestinal manifestations.