Introduction
Patients with intestinal failure (IF) have abnormalities of intestinal anatomy, secretion, and/or motility, and physiological protective mechanisms regulating small intestinal bacterial counts are impaired, which can lead to small intestinal bacterial overgrowth. There are five key mechanisms that drive intestinal failure, of which, short bowel syndrome (SBS) following surgical resection is the most common. Less frequent mechanisms include enterocutaneous fistula, dysmotility, obstruction and malabsorption. Small intestinal bacterial overgrowth (SIBO) and catheter related blood stream infections (CRBSI) are two of the most common complications with a direct impact on morbidity and mortality. Parenteral nutrition (PN) use in intestinal failure has also been proposed as an independent risk factor for development of SIBO. However, the reported prevalence of SIBO in patients with IF is variable. We thus conducted a systematic review and meta-analysis aimed to determine the prevalence of SIBO in patients with IF and to identify the risk factors that predict SIBO in this cohort.
Aims & Methods
MEDLINE (PubMed) and Embase electronic databases were searched from inception to April 2023 for studies that reported the prevalence of SIBO in IF. The prevalence rates, odds ratio (OR) and 95% confidence intervals of SIBO in IF were calculated using DerSimonian and Laird random effects model, and further subgroup analysis stratified according to mode of SIBO diagnosis and short-bowel syndrome cause of IF were conducted. This study was registered with PROSPERO (CRD42023414010).
Results
Six prevalence studies reporting on 313 patients with IF were included in this systematic review and meta-analysis. Overall, the prevalence of SIBO in IF was 55.2% (95% CI: 41.5-68.2), with considerable heterogeneity in this analysis (I2=79.2, p=0.0001), with slightly increased SIBO prevalence in IF patients on parenteral nutrition (61.1% 95% CI 31.6-84.3). There was no difference in CRBSI in SIBO positive (45.5%, 95% CI: 28.1-63.6) as compared to SIBO negative IF patients (45.7%, 95%CI 16.7-76.6). Utilizing duodenal aspirate and culture SIBO prevalence in patients with IF was significantly higher as compared to that with glucose breath test (OR 2.59, 95% CI 1.2-5.8, p=0.03), with moderate heterogeneity noted in this analysis (I2=53.9, p=0.054). There was no difference in SIBO prevalence in patients with IF due to SBS (49.1%, 95% CI 42.7-55.4) as compared to IF due to other causes (53.5%, 95%CI 37.7-68.8).
Conclusion
This systematic review and meta-analysis suggests a link between SIBO and IF, with higher SIBO prevalence in patients with IF diagnosed utilizing small bowel aspirate and culture. Parenteral nutrition appeared to be risk factor for SIBO in IF. Moreover, there was no like between SIBO and CRBSI in patients with IF. However, the results need to be interpreted with caution, due to the low sensitivity and specificity of the SIBO diagnostic tests, lack of case control studies and clinical heterogeneity seen in the prevalence studies. Further prospective studies are required to further assess the link between SIBO and IF and explore the risk factors for SIBO in IF.
