Hydrogen (H₂) breath tests serve several purposes. (i) detect malabsorption of carbohydrates such as lactose and fructose, (ii) measurement of oro-caecal transit time (iii) associate hydrogen production with the onset of abdominal symptoms like bloating, flatulence, pain, and diarrhea (which indicates carbohydrate intolerance), and (iv) diagnose small intestinal bacterial overgrowth (SIBO).
It is important to distinguish between carbohydrate intolerance and SIBO because their treatments differ significantly. Carbohydrate intolerance is typically managed through dietary restrictions, while SIBO requires antibiotic therapy. However, recent guidelines have questioned the accuracy of hydrogen breath tests in diagnosing SIBO due to variability in OCTT measurements. This limitation can be addressed by combining H₂ breath tests with imaging techniques such as scintigraphy, which independently confirm OCTT. When this combined approach is used, SIBO is diagnosed if the rise in breath H₂ occurs before the contrast agent appears in the large bowel. Despite its benefits, this combined method faces organizational and financial challenges that limit its routine clinical use.
This retrospective cohort study aims to assess the clinical performance of a cheap and simple test that combines a 20g lactulose H₂ breath test with simple radiographic abdominal imaging to assess OCTT, SIBO, and carbohydrate tolerance. The novel innovation in this method is to confirm oro-caecal transit by taking an X-ray of the abdomen when H₂ production increases during the examination. If the contrast agent is not visible in the cecum when H₂ rises, this indicates the presence of SIBO. Conversely, if the contrast agent is present in the cecum at that time, it confirms normal OCTT, and any abdominal symptoms occurring after this point support a diagnosis of carbohydrate intolerance.
If the method is proven to be valid, then this simple test will greatly facilitate the accurate diagnosis of SIBO and carbohydrate intolerance, allowing for more appropriate treatment decisions.
Patients referred for breath testing to assess the causes of digestive symptoms or maldigestion 2020-2024
Patients signed general consent to allow use of clinical data obtained during clinical assessment and breath testing to be used in research project.
None
Patients referred for breath testing to assess the causes of digestive symptoms or maldigestion 2020-2024
Cohort
Retrospective
Not listed
Practicability and safety of the novel. concurrent 20g lactulose H2 breath test with abdominal imaging
This pilot feasibility study will report the practicability and safety of the concurrent 20g lactulose H2 breath test with abdominal imaging, defined as: * Practicability / Technical success in performance of the investigation defined by (i) correct documentation of H2 production and patient symptoms using validated questionnaires (ii) timely acquisition of abdominal imaging within 20 min of H2 increase after test substance ingestion (both expressed as percentage ot total) . * Safety of the concurrent 20g lactulose H2 breath test with abdominal imaging, defined as the ability of patients (i) to ingest the test substrate (400ml) without nausea and vomiting (ii) to complete the 3-hour operating procedure without severe abdominal symptoms that require medical treatment and / or termination of test (both expressed as percentage ot total). The primary outcome measures are descriptive and not chosen to demonstrate superiority of this methodology compared to existing techniques.
Inter-rater agreement of the oro-caecal transit time
Assessment of oro-caecal transit time by radiography during 3-hour breath test study by clinician responsible for breath test procedure and also by radiologist reporting result of abdominal X-ray. Time is measured in minutes from ingestion of test substance. All cases assessed independently by two observers (gastroenterology, radiology). Agreement assessed by simple percent agreement and Cohen's kappa. Additionally, Cases in which there is disagreement as to whether contrast agent has arrived in the caecum will be reviewed by clinician, radiologist and principle investigator.
Assess prevalence of food intolerance and SIBO in patients referred for breath testing
Describe the results obtained by the concurrent 20g lactulose H2 breath test with abdominal imaging in terms of the prevalence of SIBO and food intolerance in patients referred for breath testing. A planned sub-analysis of results in patients with clinical diagnosis of IBS compared to patients with other diagnoses will also be performed.
Exploratory analysis of causes of abdominal symptoms during lactulose hydrogen breath test
Correlation of demographic (age, sex) and clinical factors (specifically presence / absence of irritable bowel syndrome based on Rome IV classification), and physiological measurements of oro-caecal transit time (minutes) and Hydrogen gas production (ppm) with the occurrence of abdominal symptoms (assessed by validated 5 point Likert scale) will be assessed by Univariate and step-wise multivariate analysis.
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Klinik Arlesheim
Lead sponsor
Kantonsspital Baselland Bruderholz
Collaborator
