SUMMARY
Background. Chronic viral hepatitis remains a leading cause of liver-related morbidity and mortality worldwide. Conventional fibrosis scoring systems, such as the FIB-4 index, are widely used for risk stratification but may fail to detect subclinical hepatic injury. Increasing evidence implicates gut dysbiosis, particularly small intestinal bacterial overgrowth (SIBO), in liver disease progression through the gut–liver axis. Aim. To investigate whether SIBO is independently associated with liver disease severity in patients with chronic viral hepatitis, beyond traditional fibrosis scores. Methods. A retrospective analysis was conducted on over 100 patients with chronic hepatitis B or C. Clinical data included SIBO breath test results, FIB-4 scores, liver enzyme levels (ALT, AST, GGT, ALP) and demographics. Patients were stratified by FIB-4 score (<1.3 vs. ≥1.3) and SIBO status. Comparative and multivariate logistic regression analyses were used to assess the predictive value of SIBO positivity after adjusting for confounders. Results. SIBO prevalence was 38% in patients with low FIB-4 scores and 61% in those with elevated scores. Notably, a subset with normal FIB-4 values but positive SIBO tests exhibited abnormal liver enzymes, suggesting hidden pathological activity. Logistic regression showed SIBO positivity to be significantly associated with hepatic enzyme elevation (p < 0.01) independent of FIB-4, age, and gender. Conclusion. SIBO positivity may serve as a novel, independent marker of hepatic stress in chronic viral hepatitis, complementing traditional fibrosis scores. Prospective studies targeting microbiota modulation could provide new therapeutic avenues.
Keywords: Small intestinal bacterial overgrowth (SIBO); Viral hepatitis; Hepatitis B virus (HBV); Hepatitis C virus (HCV); FIB-4 score

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