Abstract
INTRODUCTION: Hydrogen and methane breath testing (HMBT) is used to diagnose small intestinal bacterial overgrowth (SIBO) and intestinal methanogen overgrowth (IMO). There are limited data on whether symptoms and medical history can predict outcomes on lactulose HMBT. METHODS: A large survey-based study was conducted in 731 patients who completed lactulose HMBT at a single tertiary center in the United Kingdom. The 32-item survey included questions relating to symptoms and medical history. Survey items were statistically interrogated to determine associations with SIBO, IMO, or breath gas production using Fisher exact tests and regression models. SIBO was determined by a rise of ≥20 ppm in breath hydrogen from baseline within 90 minutes and IMO by the presence of ≥10 ppm methane in any breath sample. RESULTS: Abdominal pain ( P = 0.022), excessive belching ( P = 0.041), and regurgitation ( P = 0.034) were associated with SIBO, as well as daily abdominal pain with diarrhea ( P = 0.035), and abdominal pain or discomfort immediately after eating (odds ratio 2.20, 95% CI 1.29-3.79). Patients reporting at least 1 skin condition were more likely to test positive for SIBO, with a trend toward significance for eczema ( P = 0.051) and rosacea ( P = 0.067). IMO was associated with constipation ( P < 0.001) and with fatty/greasy stools that tend to float ( P < 0.001). DISCUSSION: This large questionnaire study demonstrated that irritable bowel syndrome-like symptoms, refractory gastroesophageal reflux symptoms, and skin conditions are associated with outcomes on HMBT. These findings support the use of HMBT in accordance with current clinical guidelines.