Testing and Treating Small Intestinal Bacterial Overgrowth Reduces Symptoms in Patients with Inflammatory Bowel Disease

Dig Dis Sci. 2018 Sep;63(9):2439-2444. doi: 10.1007/s10620-018-5109-1. Epub 2018 May 14.


Background: Common mechanisms against small intestinal bacterial overgrowth (SIBO), including an intact ileocecal valve, gastric acid secretion, intestinal motility, and an intact immune system, are compromised in inflammatory bowel disease (IBD), and therefore, a relatively high incidence of SIBO has been reported in this population.

Aims: We aimed to determine whether an improvement in IBD clinical activity scores is seen after testing and treating SIBO.

Methods: A retrospective cohort study of 147 patients with inflammatory bowel disease who were referred for SIBO breath testing from 1/2012 to 5/2016 was performed. Characteristics of SIBO positive and treated patients were compared to SIBO negative patients, including the changes in Partial Mayo Score or Harvey Bradshaw Index (HBI), using Student's t test for continuous variables and Chi-squared or Fisher's exact test for categorical variables.

Results: 61.9% were SIBO positive and treated, and 38.1% were SIBO negative. In Crohn's disease, the median HBI decreased from 5 to 3 and 5 to 4, in the SIBO positive and negative groups, respectively (p = 0.005). In ulcerative colitis, the Partial Mayo Score decreased from 2 to 1.5 and 2 to 1, respectively (p = 0.607).

Conclusions: This study examines the clinical effect of testing and treating for SIBO in an IBD population. We see a significant reduction in HBI after testing for and treating SIBO. Future prospective studies are necessary to further investigate the role of SIBO in the evaluation and management of IBD.

Keywords: Bloating; Breath test; Crohn’s disease; Ulcerative colitis.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Blind Loop Syndrome / diagnosis*
  • Blind Loop Syndrome / epidemiology*
  • Blind Loop Syndrome / therapy
  • Breath Tests / methods
  • Cohort Studies
  • Female
  • Humans
  • Inflammatory Bowel Diseases / diagnosis*
  • Inflammatory Bowel Diseases / epidemiology*
  • Inflammatory Bowel Diseases / therapy
  • Male
  • Middle Aged
  • Retrospective Studies
  • Treatment Outcome