The Prevalence of Small Intestinal Overgrowth in Irritable Bowel Syndrome VS. Healthy Controls by Using Glucose-hydrogen Breath Test in Khuzestan Province

To estimate the prevalence of small intestine bacterial overgrowth (SIBO) among patients with irritable bowel syndrome (IBS) versus healthy subjects with the use of a glucose breath test (GBT) in our geographical area.

This study included a total of 80 consecutive patients; 40 with IBS based on Rome III criteria and 40 healthy controls with similar age and sex distribution. Patients and controls underwent 50g GBT for the diagnosis of SIBO. The test was considered positive if the hydrogen concentrations in the expired air increased more than 20 ppm over basal values within 90 minutes or there were two distinct peaks during the test.

Of the 40 patients with IBS and 40 healthy controls, there were 14 males and 26 females in each group. Patients ages ranged from 22 to 66 years (mean 34 years). The majority of patients with IBS had either constipation predominant (42.5%) or mixed type IBS (30%) and 17.5% were diarrhea predominant. The prevalence of an abnormal GBT result was higher in patients diagnosed with IBS (47.5%) with respect to controls (20%, p=0.009). A positive GBT was seen in 47% of IBS constipation predominant patients, 42.9% of diarrhea predominant and in 50% of the mixed group IBS patients (p=0.85).

This study showed that approximately half of the IBS patients had SIBO. A signicant difference of SIBO, however, was not detected amongst IBS subgroups. Therefore, SIBO should be suspected in patients diagnosed with IBS and in these patients GBT might be requested.