Small intestinal bacterial overgrowth in cirrhosis: systematic review and meta-analysis

BackgroundSmall intestinal bacterial overgrowth (SIBO) was detected in cirrhosis in many studies. The aim is to perform a systematic review and meta-analysis on the prevalence of SIBO in cirrhosis and on the relationship of SIBO with features of cirrhosis.MethodsPUBMED search (until 14 January 2018) was performed. Specific search terms were: (cirrhosis) AND (SIBO OR bacterial overgrowth)'. Studies not relating to cirrhosis or SIBO, animal studies, and non-original articles were excluded. A meta-analysis of all studies was performed using a random-effects model.Results117 references were identified by the PUBMED search. 3 references were added after handsearching the reference lists of all the articles. 99 references were excluded. 21 studies (included in total 1264 cirrhotics and 306 controls) remained for qualitative analysis and quantitative synthesis. Prevalence of SIBO for cirrhosis was 40.8% (95% CI 34.8-47.1), while the prevalence of SIBO for controls was 10.7% (95% CI 5.7-19.0). OR 6.83 (95% CI 4.16-11.21; p<0.001). Prevalence of SIBO for decompensated cirrhosis was higher than prevalence of SIBO for compensated cirrhosis (50.5% vs. 31.2%; p<0.001). SIBO in cirrhosis was associated with ascites (p<0.001), minimal hepatic encephalopathy (p=0.001), bacterial translocation (p=0.026), spontaneous bacterial peritonitis (p=0.008), prolonged orocecal transit time (p<0.001), and was not associated with hypocoagulation. Further studies are required to clarify the relationship of SIBO with hyperbilirubinemia, hypoalbuminemia, overt hepatic encephalopathy in past, esophageal varices and systemic inflammation.ConclusionSmall intestinal bacterial overgrowth is more often detected in cirrhosis than in healthy persons and is associated with some features of cirrhosis.