S1359 Determinants and Outcomes of Pre-Test Elevation in Hydrogen/Methane Breath Testing for SIBO

Abstract

Introduction: Small intestinal bacterial overgrowth (SIBO) is characterized by excess colonic microbe colonization in the small bowel. This can result in malabsorption, and patients typically present with a wide array of gastrointestinal symptoms, making it difficult to diagnose through clinical presentation alone. Diagnosis is established by elevated hydrogen or methane levels on breath test. It has been hypothesized that hydrogen dominant SIBO is associated with diarrhea while methane dominant is associated with constipation. We aimed to assess whether lifestyle factors, certain risk factors or common symptoms are characteristic of SIBO positivity. Methods: Patients undergoing SIBO breath testing (n=308) were surveyed. The survey included questions about stool frequency, stool consistency, PPI usage, antibiotic usage, dietary factors, and symptoms. Results from the survey and breath test were compared. Results: When comparing PPI usage, antibiotic usage, experienced symptoms, kefir/yogurt/probiotic ingestion, stool consistency, or stool frequency no significant difference was found between patients who tested positive versus negative for SIBO (Table 1). However, patients who did not have a daily stool had double the odds of having a positive breath test (OR = 0.50, CI: [0.28-0.88]). Additionally, the mean age for patients tested positive for SIBO (59.62) was significantly higher than patients tested negative for SIBO (52.14)(P = < 0.001). Conclusion: SIBO is a difficult to characterize disease with a variety of symptoms. When assessing patients’ dietary factors (kefir, yogurt, or probiotic ingestion), risk factors (PPI and antibiotic usage), and experienced symptoms, no unifying variable predictive of SIBO positivity was determined. Interestingly, patients who did not at least have a daily stool had double the odds of having a positive breath test, possibly suggesting the predominance of constipation-like symptoms in SIBO positive patients in this population. Additionally, the mean age for patients positive for SIBO was significantly higher than patients tested negative for SIBO. Further research is necessary to characterize lifestyle and clinical factors influencing SIBO positivity and to understand the intricacies between breath testing and patient symptoms.Figure 1.: Figure 1a and 1b: Proportions with Positive vs Negative SIBO Breath TestTable 1.: Demographics and Variables Affecting SIBO Positivity.