Small intestinal bacterial overgrowth in chronic liver disease: an updated systematic review and meta-analysis of case-control studies.

BACKGROUND

Small Intestinal Bacterial Overgrowth (SIBO) has been implicated in the pathophysiology of chronic liver disease (CLD). We conducted a systematic review and meta-analysis to assess and compare the prevalence of SIBO among CLD patients (with and without with complications of end stage liver disease) and healthy controls.

METHODS

Electronic databases were searched from inception up to July-2024 for case-control studies reporting SIBO in CLD. Prevalence rates, odds ratios (ORs), and 95% confidence intervals (CIs) of SIBO in patients with CLD and controls were calculated utilizing a random-effects model. The protocol was prospectively registered with PROSPERO (CRD42022379578).

FINDINGS

The final dataset included 34 case-control studies with 2130 CLD patients and 1222 controls. Overall, the odds for SIBO prevalence in CLD patients compared to controls was 6.7 (95% CI 4.6-9.7, p < 0.001). Although the prevalence of SIBO among patients with CLD with cirrhosis was higher at 42.9% (95% CI: 35.9-50.2) compared to 36.9% (95% CI: 27.4-47.6) in those without cirrhosis, this difference failed statistical significance. However, CLD patients with decompensated cirrhosis had a significantly higher prevalence of SIBO compared to those with compensated cirrhosis, with an OR of 2.6 (95% CI: 1.5-4.5, p < 0.001). Additionally, the prevalence of SIBO was significantly higher in CLD patients with portal hypertension (PHT) than in those without PHT, with an OR of 2.1 (95% CI: 1.4-3.1, p < 0.001). The highest prevalence of SIBO was observed in patients with spontaneous bacterial peritonitis (SBP) (57.7%, 95% CI 38.8-74.5), followed by patients with hepatic encephalopathy (41.0%, 95% CI 16.0-72.3) and patients with variceal bleed (39.5%, 95% CI 12.1-75.6).

INTERPRETATION

Overall, there is a significantly increased prevalence of SIBO in CLD patients compared to controls. The prevalence is even higher in CLD patients with PHT, especially those with SBP. This meta-analysis suggests that SIBO is associated with complications of CLD and potentially linked to the progression of CLD.

FUNDING

National Health and Medical Research Council, Centre for Research Excellence (APP170993).