Risk Factors of Colorectal Stricture Associated with Developing High-Grade Dysplasia or Cancer in Ulcerative Colitis: A Multicenter Long-term Follow-up Study.

Background/Aims: The risk factors of colorectal stricture associated with ulcerative colitis (UC) carcinogenesis in the long-term disease duration remain unclear. Methods: This study included all UC patients registered from a prospectively maintained database between June 1986 to July 2018. The demographic data, clinical features, and outcomes in patients with dysplasia and stricture were assessed using univariable analysis and multivariate logistic regression models. Results: A total of 246 eligible patients were included in the analysis. The median follow-up time was 13.0 years (interquartile range [IQR], 9.0 to 16.0). There were 35 cases (14.2%) of colorectal stricture. Patients with stricture had worse clinical outcomes. Stricture formation (odds ratio [OR], 9.350; 95% confidence interval [CI], 2.842 to 30.762), inflammatory polyps (OR, 5.464; 95% CI, 1.692 to 17.638), disease duration of more than 10 years (OR, 3.223; 95% CI, 1.040 to 9.985), and age >40 years at diagnosis (OR, 8.499; 95% CI, 1.903 to 37.956) were significantly associated with high-grade dysplasia or colorectal cancer. In addition, disease duration of more than 5 years (OR, 3.211; 95% CI, 1.168 to 8.881), moderated anemia (OR, 3.373; 95% CI, 1.472 to 7.731), and primary sclerosing cholangitis (OR, 5,842; 95% CI, 1.395 to 24.468) were contributing factors for the development of colorectal stricture. Conclusions: Colorectal stricture had the highest risk for malignant transformation. Earlier initiation of colonoscopic surveillance in UC patients with risk factors for stricture should be considered to prevent stricture formation and further malignant transformation.