What tests should you use to assess small intestinal bacterial overgrowth in systemic sclerosis?

OBJECTIVES: Small intestinal bacterial overgrowth (SIBO) plays a major role in the pathogenesis of malabsorption in SSc patients and is a source of great morbidity and even mortality, in those patients. This manuscript reviews which tests are valid and should be used in SSc when evaluating SIBO. METHODS: We performed systematic literature searches in PubMed, Embase and the Cochrane library from 1966 up to November 2014 for English language, published articles examining bacterial overgrowth in SSc (e.g. malabsorption tests, breath tests, xylose test, etc). Articles obtained from these searches were reviewed for additional references. The validity of the tests was evaluated according to the OMERACT principles of truth, discrimination and feasibility. RESULTS: From a total of 65 titles, 22 articles were reviewed and 20 were ultimately extracted to examine the validity of tests for GI morphology, bacterial overgrowth and malabsorption in SSc. Only 1 test (hydrogen and methane breath tests) is fully validated. Four tests are partially validated, including jejunal cultures, xylose, lactulose tests, and 72 hours fecal fat test. CONCLUSIONS: Only 1 of a total of 5 GI tests of bacterial overgrowth (see above) is fully validated in SSc. For clinical trials, fully validated tests are preferred, although some investigators use partially validated tests (4 tests). Further validation of GI tests in SSc is needed.