Small-Intestinal Bacterial Overgrowth is Associated With Concurrent Intestinal Inflammation But Not With Systemic Inflammation in Crohn's Disease Patients.

Goals: We studied the prevalence and predictors of small-intestinal bacterial overgrowth (SIBO) in Crohn's disease (CD) outpatients and the relationship between SIBO and intestinal and/or systemic inflammation.

Background: The relationship of SIBO with systemic and intestinal inflammation in CD patients is unclear.

Study: In this cross-sectional study, conducted between June, 2013 and January, 2015, 92 CD patients and 97 controls with nonchronic gastrointestinal complaints were assessed for the presence of SIBO using the H2/CH4 glucose breath test. Multivariate logistic regression was performed to investigate the potential association between SIBO and demographic, disease-related data, systemic markers of inflammation (C-reactive protein, and erythrocyte sedimentation rate), and biomarker of intestinal inflammation [fecal calprotectin concentration (FCC)].

Results: The SIBO rate was significantly higher in CD patients than in controls (32.6% vs. 12.4%, respectively, P=0.0008). Patients with and without SIBO were comparable with regard to demographics, systemic inflammatory biomarkers, and disease characteristics, except for the stricturing phenotype being more common in SIBO-positive CD patients (43.3% vs. 19.3%, P=0.015). Notably, FCC was significantly higher in SIBO-positive patients (median of 485.8 vs.132.7 μg/g; P=0.004). Patients presenting increased FCC and stricturing disease had an odds of 9.43 (95% confidence interval, 3.04-11.31; P<0.0001) and 3.83 (95% confidence interval, 1.54-6.75; P=0.025) respectively, for SIBO diagnosis.

Conclusions: In CD patients, SIBO is a highly prevalent condition. Stricturing phenotype and increased FCC were strongly and independently associated with the presence of SIBO. SIBO diagnostic work-up followed by directed treatment is recommended in CD patients who present stricturing disease, especially in those with concurrent intestinal inflammation.