Small intestinal bacterial overgrowth in gastroparesis: are there any predictors?

There is some degree of overlap in the symptomatic spectrum of patients with gastroparesis and small intestinal bacterial overgrowth (SIBO) and some of the etiologies for gastroparesis, such as diabetes mellitus and vagotomy are known to predispose to SIBO. The aims of our study were to measure the prevalence of SIBO in a cohort of gastroparetic patients with prominence of abdominal pain and bloating and try to identify predictors with regard to demographics, concurrent use of medications such as prokinetics, proton pump inhibitors, and opiate analgesics, and predominant bowel movement abnormality.

Glucose breath testing (GBT) for SIBO was performed in 50 patients (41 females) with gastroparesis. Demographic data, medication profiles, baseline and peak measurements of hydrogen or methane gas on the GBT, and results of the most recent gastric emptying scintigraphy test were recorded.

Thirty of fifty (60%) patients had a positive GBT for SIBO on the basis of hydrogen (63%), methane (27%), or both criteria (10%). SIBO was more likely (P=0.001) in patients with gastroparetic symptoms of greater duration (mean 5 y; 95% CI: 4-6 y). No significant differences were noted in both groups with regard to age, sex, or etiology of gastroparesis. Gastric emptying was similar in the SIBO and non-SIBO group (P>0.05). After adjusting for tegaserod and opiate analgesic use, 14/23 (61%) had a positive GBT.

SIBO is very common in gastroparetics with predominance of abdominal pain and bloating, especially those with a longer duration of gastroparesis. Awareness of SIBO in the setting of gastroparesis will facilitate separation of the 2 entities and allow appropriate therapies to be instituted.