Risk factors and prognostic value of acute severe lower gastrointestinal bleeding in Crohn's disease

BACKGROUND Acute severe lower gastrointestinal bleeding (LGIB) is an uncommon but challenging complication of Crohn's disease (CD). AIM To identify the predictors of acute severe LGIB and to evaluate the impact of acute severe LGIB on the subsequent clinical course in CD patients. METHODS A retrospective inception cohort study was conducted in 75 CD patients with acute severe LGIB and 1359 CD patients without acute severe LGIB who were diagnosed between February 1991 and November 2019 at Asan Medical Center, a tertiary university hospital in Korea. Multivariable analysis with Cox proportional hazard regression was performed to identify the risk factors for acute severe LGIB. A matched analysis using 72 patients with bleeding and 267 matched patients without within the cohort was also conducted to investigate whether acute severe LGIB is a predictor of clinical outcomes of CD. RESULTS Multivariable Cox regression analysis revealed that early use of thiopurines [hazard ratio (HR): 0.23, 95% confidence interval (CI): 0.12-0.48; P < 0.001] and female sex (HR: 0.51, 95%CI: 0.27-0.94; P = 0.031) were significantly associated with a lower risk of acute severe LGIB. The cumulative risks of behavioral progression and intestinal resection were not significantly different between the two matched groups (P = 0.139 and P = 0.769, respectively). The hospitalization rate was higher in the bleeding group than in the matched non-bleeding group (22.1/100 vs 13.2/100 patient-years; P = 0.012). However, if hospitalizations due to bleeding episodes were excluded from the analysis, the hospitalization rate was not significantly different between the bleeding group and the matched non-bleeding group (14.5/100 vs 13.2/100 patient-years; P = 0.631). CONCLUSION Early use of thiopurines may reduce the risk of acute severe LGIB. History of acute severe LGIB may not have a significant prognostic value in patients with CD.