Association between chronic use of proton pump inhibitors and small- intestinal bacterial overgrowth assessed using lactulose hydrogen breath tests.

BACKGROUND/AIMS: Several adverse events have been reported in patients who are chronic users of proton pump inhibitors (PPIs); however, the association between PPI use and small-intestinal bacterial overgrowth (SIBO) is controversial. We examined the prevalence of SIBO, as assessed by the lactulose hydrogen breath test (LHBT), based on the use of gastric acid-suppressive drugs in Japanese patients. METH- ODOLOGY: Ninety-four patients who were examined by the LHBT were assessed retrospectively. We used several criteria to define a positive LHBT result. Nine patients received probiotics containing Lactobacillus casei.

RESULTS

Fifty patients were PPI users, 14 were histamine-2 receptor antagonist (H2RA) users, and were 30 non-PPI and non-H2RA users (controls). There were no significant differences in prevalence of LHBT-positive cases among the three groups. Multiple-adjusted regression showed no significant association between PPI use and being LHBT-positive. Prevalence of postprandial fullness in PPI users was high (46%), but such symptoms were not related to LHBT results. Four (44%) of 9 cases became LHBT-negative and the maximal peak of H2 production decreased significantly after probiotic treatment.

CONCLUSIONS

PPI treatment is not associated with SIBO in Japanese patients. Mechanisms apart from SIBO could cause the high prevalence of postprandial fullness in PPI users.