Background: There is growing interest in hydrogen sulfide small intestinal bacterial overgrowth (H2S SIBO). However, basic questions including how clinicians are making the diagnosis, what symptoms are present, and what clinicians are using for treatment, remain unanswered. Aims: To address this, we created an online, survey-based, clinical registry of H2S SIBO cases. Methods: Participants in this study were clinicians diagnosing and treating patients with H2S SIBO and input data on patient presentation, diagnosis, treatment, and treatment response. We describe the population and summarize our results using descriptive statistics. We use Pearson's chi-squared test and modified Poisson regression in exploratory analyses. Results: 131 total cases were submitted by 99 providers across a spectrum of health disciplines. The mean patient age was 45.6 (71.4% female). The most common symptoms were bloating (77.0%), constipation (50.8%) and abdominal pain (50.8%). Diagnosis was made based on flatline hydrogen in the 3rd hour of a lactulose breath test (42.5%), symptom presentation (empiric) (31.9%), or H2S levels (25.7%). The most common treatments used were a low sulfur diet (46.6%), oregano (44.0%), and bismuth (39.7%). Fifty-eight percent of cases were responders. Of the most common interventions used, only a low sulfur diet (73% responder; p=0.01) and bismuth (76% responder; p=0.01) were significantly associated with treatment response. Interestingly, response rates differed based on how H2S SIBO was diagnosed, with empiric underperforming flatline diagnoses (relative risk 0.60; p=0.04). Conclusions: This case registry represents the largest collection of H2S SIBO cases to-date, providing important early descriptive information on this emerging diagnosis.

The authors have declared no competing interest.

This research was supported by individual donors, the Gastroenterology Association of Naturopathic Physicians, and in-kind donation from the Helfgott Research Institute.

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This research was reviewed and approved for exemption status by the institutional review board of the National University of Natural Medicine (registration number JG41321). Informed consent was obtained from all participants.

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