Small intestinal bacterial overgrowth in patients with inflammatory bowel disease: A case-control study

Background Though small intestinal bacterial overgrowth (SIBO) is known in inflammatory bowel disease (IBD), the data on it are scanty and have limitations. Methods Data on IBD patients undergoing glucose hydrogen breath test (GHBT) were retrospectively analyzed to evaluate the frequency and risk factors of SIBO in IBD compared to 66 healthy controls. Results Patients with IBD (n=86; 45 ulcerative colitis [UC] and 41 Crohn's disease [CD]) more often had SIBO on GHBT than the healthy subjects (16/86 [18.6%] vs. 1/66 [1.5%]; p=0.002). SIBO was commoner among patients with CD than UC (14/41 [34.1%] vs. 2/45 [4.4%]; p=0.001). The frequency of SIBO among UC patients was comparable to healthy subjects (2/45 [4.4%] vs. 1/66 [1.5%]; p=not significant [NS]). Patients with CD than those with UC had higher values of maximum breath hydrogen and a greater area under the curve for breath hydrogen. Other factors associated with SIBO included female gender (11/16 [68.8%] with vs. 21/70 [30%] without SIBO; p=0.003), and having undergone surgery (8/16 [50%] vs. 6/70 [8.6%]; p=0.0002). SIBO patients had lower levels of total serum protein and albumin than those without SIBO (6.2 +/- 1.5 g/dL vs. 7.0 +/- 0.9 g/dL, respectively; p=0.009 and 3.5 +/- 0.9 g/dL vs. 4.0 +/- 0.6 g/dL, respectively; p=0.02). CD, female gender, and surgery for IBD tended to be the independent factors associated with SIBO among IBD patients on multivariate analysis. Conclusions Patients with IBD, particularly CD, female, and those having undergone surgery, have a higher risk of SIBO than the healthy controls.

Automated summary

Patients with inflammatory bowel disease (IBD), especially those with Crohn's disease (CD), female gender, and a history of surgery, have a higher risk of small intestinal bacterial overgrowth (SIBO) compared to healthy controls, as shown by the results of glucose hydrogen breath testing (GHBT). Factors associated with SIBO included female gender, surgical history, lower levels of total serum protein and albumin, as well as higher values of maximum breath hydrogen and area under the curve for breath hydrogen in CD patients.