The Prevalence of Small Intestinal Bacterial Overgrowth in Diabetes Mellitus: A Systematic Review and Meta-analysis

Objective: The reported prevalence of small intestinal bacterial overgrowth (SIBO) among patients with diabetes mellitus (DM) is highly variable. We conducted this systematic review and meta-analysis to estimate the prevalence of SIBO in DM.Methods: A comprehensive literature search of the PubMed, Cochrane Library and Embase databases from inception to December 2020 was conducted for studies correlating SIBO with DM. Studies were screened, and relevant data were extracted and analysed. The pooled prevalence of SIBO among DM patients and the odds ratio (OR) of SIBO among DM patients compared with controls were calculated. Publication bias was assessed using Egger’s test and funnel plots.Results: Fourteen studies including 1417 diabetes patients and 649 controls met the inclusion criteria. The pooled prevalence of SIBO in DM was 29% (95% CI 20–39%). The OR of SIBO in diabetes patients was 2.91 (95% CI 0.82–10.32, p=0.1) compared with controls. Subgroup analyses showed that the prevalence of SIBO in DM was higher in studies using jejunal aspirate culture (JAC) for diagnosis (39%, 95% CI 12–66%) than in those that used the lactulose breath test (LBT) (31%, 95% CI 18–43%) or glucose breath test (GBT) (29%, 95% CI 14–43%). The prevalence of SIBO in DM was higher in studies conducted in Western countries (35%, 95% CI 21–49%) than in those conducted in Eastern countries (24%, 95% CI 14–34%), and the prevalence of SIBO in type 1 DM (25%, 95% CI 14%–36%) was not significantly different from that in type 2 DM (30%, 95% CI 13%–47%).Conclusion: Twenty-nine percent of diabetes patients tested positive for SIBO and had a significantly higher risk than the controls. The prevalence of SIBO in DM varied according to the diagnostic test performed and geographic area. DM could be a predisposing factor for the development of SIBO, especially among patients diagnosed by JAC or those in Western populations.