S1153 Small Intestinal Bacterial Overgrowth in Functional Dyspepsia and Its Subtypes: A Systematic Review and Meta-Analysis

Introduction: Functional dyspepsia disease (FD) is a common condition affecting the gastroduodenal area, characterized mainly by the symptoms of postprandial fullness or epigastric pain that could not be attributed to any underlying organic disease for a period of 6 months. Small intestinal bacterial overgrowth (SIBO) is a medical condition where there are alterations in the quantity and distribution of gut microbiota. The SIBO prevalence in FD and its subtypes remains unclear, with conflicting estimates. Hence, this systematic review was conducted to provide a pooled prevalence of SIBO in FD patients, and compare it to healthy individuals by odds ratio, in addition to investigating the variations in the techniques used for SIBO diagnosis across the studies. Methods: Four databases were reviewed to identify relevant literature. Studies reporting the SIBO prevalence in FD or giving sufficient data to calculate it were included. Pooled prevalence was calculated for all studies, and an odds ratio (OR) was calculated for the studies having a healthy control group. Sensitivity analysis, publication bias assessment, and quality assessment were done. Subgroup analysis was done to examine variations by regions and diagnostic criteria. Results: Eleven studies with 792 FD patients from 10 countries were identified. The pooled SIBO prevalence in FD subjects was 25.8% (95% CI: 16.1%–38.6%, I² = 90.16%). As pooled from 8 case-control studies, FD patients reported significantly higher odds of SIBO when put in comparison with healthy subjects (OR = 5.13, 95% CI: 2.62–10.06, I² = 10.65%). Subgroup analysis revealed higher prevalence estimates when using lactulose as a substrate for hydrogen breath test (HBT) compared to glucose. Grouping by region identified the Americas as the region with the highest reported prevalence. There are variations in the diagnostic techniques and parameters across the studies. Sensitivity analyses confirmed the robustness of the findings, and no publication-related bias was found. Conclusion: SIBO is prevalent among FD patients, and FD patients are at higher risk to have SIBO when compared to controls. No major differences were found in SIBO prevalence for FD subtypes. Future research should standardize diagnostic parameters to provide more accurate estimates.