Prevalence and Risk Factors of Acute Lower Gastrointestinal Bleeding in Crohn Disease

Acute lower gastrointestinal bleeding (ALGIB) is a rare but potentially life-threatening complication of Crohn disease (CD). Thus far, few studies of ALGIB in the context of CD have been published, most of which were case reports with limited value. We aimed to explore the prevalence of ALGIB in CD patients, evaluate risk factors for hemorrhagic CD and its recurrence, and analyze clinical data of the death cases.A total of 1374 CD patients registered from January 2007 to June 2013 were examined. Medical records of 73 patients with ALGIB and 146 matched as controls were reviewed and analyzed retrospectively. Logistic regression and Cox proportional hazards analyses were performed to identify risk factors for ALGIB and the cumulative probability of rebleeding. Kaplan-Meier curves with log-rank tests were used to demonstrate the cumulative survival rates of rebleeding.The prevalence of ALGIB was 5.31% (73/1374) in this study. In the univariate analysis, possible risk factors for ALGIB were duration of CD (odds ratio [OR] 0.60, 95% confidence interval [CI] 0.33-1.09, P = 0.095), perianal disease (OR 1.96, 95% CI 0.92-4.20, P = 0.082), left colon involvement (OR 2.16, 95% CI 1.10-4.24, P = 0.025), azathioprine use ≥1 year (OR 0.46, 95% CI 0.23-0.90, P = 0.023), and previous hemorrhage history (OR 11.86, 95% CI 5.38-26.12, P < 0.0001). In the multivariate analysis, left colon involvement (OR 2.26, 95% CI 1.04-4.91, P = 0.039), azathioprine use ≥1 year (OR 0.44, 95% CI 0.20-0.99, P = 0.044), and previous hemorrhage history (OR 13.04, 95% CI 5.66-30.04, P < 0.0001) remained independent influencing factors. Older age (HR 0.23, 95% CI 0.07-0.77, P = 0.018), surgical treatment (HR 0.17, 95% CI 0.06-0.50, P < 0.001), and having bleeding episodes >3 months ago (HR 0.24, 95% CI 0.07-0.82, P = 0.022) resulted to be predictors associated with rebleeding after discharge. Patients who died often suffered severe concomitant diseases, and the overall mortality rate was 8.22% (6/73).We speculated that a special hemorrhagic phenotype of CD that was predisposed to rebleeding may exist. Further studies are warranted to investigate the pathogenesis and discover the optimum treatments of choice.