Small‐intestinal bacterial overgrowth in cirrhosis is related to the severity of liver disease

BACKGROUND: Small-intestinal bacterial overgrowth (SIBO) is known to be present in patients with cirrhosis, predisposing to various complications. AIM: To determine the frequency of SIBO in cirrhotics and correlate with severity of cirrhosis. METHODS: Small-intestinal bacterial overgrowth was determined by glucose-hydrogen breath test (GHBT). A basal breath-hydrogen >20 ppm or a rise by > or = 12 ppm above baseline following glucose administration was taken as positive test. Prevalence of SIBO in cirrhotics was compared with healthy controls and correlated with severity of cirrhosis. RESULTS: Of the 53 cirrhotics, 26 (49%) had SIBO, compared to one (8%) control (P = 0.010). The prevalence of SIBO increased with severity of cirrhosis (Child-Pugh A 20%, B 52% and C 73%; P = 0.013). On multivariate analysis, SIBO was independently associated with serum bilirubin and ascites. The best cut-off of serum bilirubin was >/=2 mg/dL [AUROC 0.77 (95% CI 0.64-0.90)] predicting SIBO with sensitivity 65%, specificity 81%, positive predictive value 77%, negative predictive value 71% and accuracy 74%. Patients having combination of ascites and serum bilirubin > or = 2 mg/dL had 82% chance, while patients having neither had only 10% chance of having SIBO. CONCLUSIONS: Small-intestinal bacterial overgrowth was prevalent in about half of cirrhotics. Its frequency increased with increase in severity of cirrhosis. Ascites and raised serum bilirubin reliably predicted presence of SIBO.