Patients with irritable bowel syndrome exhale more hydrogen than healthy subjects in fasting state

Irritable bowel syndrome (IBS) is a common disorder with significant morbidity and impairment of quality of life. Most patients (26%-83%) with IBS from Asia reported bloating. Bloating may result from increased amount or distribution of gas in the gut or exaggerated perception of distension. To evaluate whether patients with IBS produce more hydrogen even in fasting state, we conducted a study with the following aims: (1) to estimate fasting breath hydrogen levels among patients with IBS as compared with healthy controls (HC) and (2) to study relationship between symptoms of IBS and stool frequency and fasting breath hydrogen levels.

Eighty-one patients with IBS (Rome III criteria) and 123 HC were included. Hydrogen breath test was performed using a gas analyzer after an overnight (12 hours) fast. Both patients with IBS and HC had similar preparation before breath hydrogen estimation.

Of 93 patients with symptoms of functional gastrointestinal disorders, 81 (87.1%) met Rome III criteria and 12 (12.9%) were negative and hence, excluded from the study. Patients with IBS were comparable in age (35 +/- 11.8 years vs 37.5 +/- 13.1 years, p = NS) and gender (male 61/81 [75.3%] vs 77/123 [62.6%], p=0.67) with HC. Average fasting breath hydrogen was higher in patients with IBS as compared to HC (mean 10.1 +/- 6.5 ppm vs 5.5 +/- 6.2 ppm, p < 0.0001). Number of stools per week correlated with average fasting breath hydrogen excretion in patients with IBS (r = 0.26, p = 0.02).

Inspite of similar preparation for the test, fasting breath hydrogen was higher in patients with IBS as compared to HC. Number of stools per week correlated with fasting breath hydrogen levels among patients with IBS.