Background: Both natural history and treatment outcome of hepatitis B virus (HBV) infection are influenced by genotypes and viral load. Information about factors determining HBV genotype distribution and viraemia in HIV/HBV-co-infected patients is scarce.
Methods: All HIV-positive patients living in Europe and Argentina recruited in EuroSIDA (1994-2006) were tested for serum HBV surface antigen (HBsAg). Chronic carriers were further characterized virologically at one central laboratory. Variables influencing HBV genotype distribution and viraemia were assessed using logistic regression.
Results: From 16 505 HIV patients enrolled in EuroSIDA, 1179 (7.1%) were HBsAg positive, of whom 474 had specimens that allowed inclusion in the virological substudy. Overall 293 (62%) were treated with anti-HBV active antiretroviral drugs at the time of testing. Hepatitis delta virus superinfection was recognized in 14% and hepatitis C virus (HCV) antibodies in 27%. Serum HBV DNA was detectable in 315 (66.5%) and HBV genotyping gave results in 170 (35.9%) patients. HBV genotype distribution was as follows: A (72.9%), D (17.1%), G (1.8%), E (1.2%), F (1.2%) and C (0.6%); another 5.9% were co-infected with multiple HBV genotypes. In the multivariate analysis, the best predictor of HBV genotype A infection was risk exposure other than intravenous drug use, whereas predictors for detectable HBV viraemia were lower CD4 counts and lack of HCV antibodies.
Conclusion: A substantial proportion of HIV-positive patients with chronic hepatitis B show detectable HBV viraemia despite being treated with anti-HBV active antiretroviral drugs (mainly lamivudine). Low CD4 counts were associated with an independent higher risk of detectable HBV viraemia, which supports an earlier introduction of antiretroviral therapy, including anti-HBV drug(s) more potent than lamivudine.