Association between occult hepatitis B infection and the risk of hepatocellular carcinoma: a meta-analysis

The association between occult hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC) remains controversial.

We conducted a meta-analysis of prospective studies and retrospective studies to examine whether occult HBV infection increases the risk of HCC.

Two independent reviewers searched databases for eligible studies published in English or Chinese dated from 1966 to 6 April 2010. The odds ratios or the relative risks (RRs) of each study were considered respectively.

We identified 16 eligible studies. A significantly increased risk of HCC was found in subjects with occult HBV infection in comparison with non-infected controls in both retrospective [OR(unadjusted) =6.08, 95% confidence interval (CI)=3.45-10.72] and prospective studies (RR(adjusted) =2.86, 95% CI=1.59-4.13), and occult HBV increased the risk for HCC in both hepatitis C virus (HCV)-infected populations (summary RR=2.83, 95% CI=1.56-4.10) and in non-infected populations (OR(unadjusted) =10.65, 95% CI=5.94-19.08). A higher prevalence of occult HBV was observed in individuals who were positive for anti-HBs and anti-HBc (OR(unadjusted) =1.81, 95% CI=1.06, 3.09).

Our findings suggest that occult HBV infection was associated with an increased risk of HCC. Occult HBV may serve as a cofactor in the development of HCV-related HCC, and it may also play a direct role in promoting Non-B and Non-C HCC growth. Suggestive evidence indicates that individuals with a concomitant presence of anti-HBs and anti-HBc had an increased risk of occult HBV infection. However, further studies are needed to clarify these observations.