[Clinical features of ulcerative colitis in patients with small intestinal bacterial overgrowth]

Objective: To explore the relationship between intestinal bacterial overgrowth (SIBO) and ulcerative colitis (UC). Methods: From December 2023 to June 2024, 85 patients with UC from the Gastroenterology Department of the Luquan branch of the Second Hospital of Hebei Medical University were enrolled. The lactulose hydrogen-methane breath test was performed to assess the prevalence of SIBO. Clinical data, including basic information, clinical manifestations, endoscopic manifestations, inflammatory indicators, current medication regimen, and past medical history, were collected. Furthermore, the body mass index (BMI), modified Mayo score, and patient-reported outcome (PRO2) score were calculated to evaluate disease activity in each patient. The Student's t-test, Chi-square test, non-parametric test, and multiple logistic regression were used to analyze the data and explore the relationship between SIBO and UC. Results: The incidence of abdominal pain and bloating in patients who were SIBO positive with UC was higher than in those who were SIBO negative [abdominal pain: 50.0%(10/20) vs. 23.1%(15/65), χ²=5.34, P=0.021; abdominal distension: 40.0% (8/20) vs. 13.8% (9/65), χ²=5.01, P=0.025]; the difference was statistically significant (P<0.05). Patients who were SIBO positive with UC were more likely to develop hypoproteinemia and anemia than those who were SIBO negative [hypoproteinemia: 50.0% (10/20) vs. 15.4% (10/65), χ²=8.35, P=0.004; anemia: 35.0% (7/20) vs. 9.2% (6/65), χ²=5.98, P=0.014]; the difference was statistically significant (P<0.05). In the intestinal methanogen overgrowth (IMO) positive group, the number of patients with UC with 1-2 stool times/day was higher, and the distribution of stool times between the IMO positive and IMO negative groups was significantly different (χ²=6.45, P=0.040). Furthermore, combined hypoproteinemia and anemia were risk factors for SIBO in patients with UC (hypoproteinemia OR=4.331, 95%CI 1.117-16.799, P=0.034; anemia OR=5.515, 95%CI 1.231-24.700, P=0.026). Conclusions: We observed a clinical overlap between SIBO and UC. SIBO could be targeted to optimize the treatment of patients with UC in the future.