Are Helicobacter Pylori and Other Helicobacter Species Infection Associated with Human Biliary Lithiasis? A Meta-Analysis

BACKGROUND Since the isolation of Helicobacter species in biliary system, a hypothetical question was raised about the role of these agents in the development of cholelithiasis. This meta-analysis is to explore the association between the Helicobacter infection and biliary lithiasis. METHODOLOGY/PRINCIPAL FINDINGS A systematic literature search was performed to identify all eligible articles. Meta-analysis which was carried out using odds ratio and random effect model, 95% confidence intervals for odds ratio was calculated. Quantitative assessment of heterogeneity was explored by chi-square test with significance set at P value 0.10 and was measured using I(2) statistic. Eighteen studies published between 1998 and 2011 were finally eligible for meta-analysis. H. pylori, H. bilis, H. hepaticus, H. pullorum and H. ganmani were studied. With heterogeneity (I(2) = 69.5%, P<0.0001), significantly higher pooled infection rates of H. pylori (OR: 2.59, 35.82% versus 26.75%, P = 0.01) and H. hepaticus (OR: 3.13, 31.30% versus 12.12%, P = 0.02) were observed in lithiasis group. Higher prevalence of H. pylori in cholelithiasis patients were reported by studies from East Asia, South Asia and South America. Evidences supporting the higher presence of H. pylori in cholelithiasis patients could be found by PCR for detecting 16s rRNA in bile, 26 kDa protein gene in biliary tissue and immunohistochemistry. Using multiple detection tests could increase the detection rate of H. pylori. CONCLUSIONS/SIGNIFICANCES Our meta-analysis suggests a trend of higher presence of H. pylori in cholelithiasis patients than control group and this trend was significant in the regions with higher prevalence of this agent. Evidences supporting the association between Helicobacter and cholelithiasis could be found by using different tests but the gold standard for the identification of these bacteria in biliary system has yet to be established. Considering obvious heterogeneity, a large multi-center study will facilitate us to further clarify the association between the Helicobacter infection and cholelithiasis.