Factors associated with isolated anti‐hepatitis B core antibody in HIV‐positive patients: impact of compromised immunity

Summary. In regions that are hyperendemic for chronic hepatitis B virus (HBV) infection, prevalence of and risk factors associated with isolated anti‐hepatitis B core antibody (anti‐HBc) in HIV‐positive patients are less well described. HIV‐positive patients who were tested for hepatitis B surface antigen (HBsAg), anti‐hepatitis B surface antibody (anti‐HBs) and anti‐HBc at designated hospitals for HIV care in Taiwan were included for analysis. HBV DNA was detected by real‐time polymerase chain reaction in patients with and without isolated anti‐HBc. Of 2351 HIV‐positive patients, 450 (19.1%) were HBsAg positive, 411 (17.5%) were anti‐HBc positive alone and 963 (41.0%) for both anti‐HBs and anti‐HBc. Compared with patients who were positive for both anti‐HBs and anti‐HBc, patients with isolated anti‐HBc were older, less likely to have anti‐hepatitis C virus antibody (anti‐HCV), had lower CD4 lymphocyte counts and higher plasma HIV RNA loads. Older age (adjusted odds ratio, 1.029; 95% confidence interval, 1.015–1.043) and CD4 <100 cells/μL (adjusted odds ratio, 1.524; 95% confidence interval, 1.025–2.265) were independently associated with isolated anti‐HBc by logistic regression, while presence of anti‐HCV and injecting drug use were not. HBV DNA was detectable in 8.3% of 277 patients with isolated anti‐HBc and 14.3% of 56 patients with both anti‐HBs and anti‐HBc (P = 0.160). In a country hyperendemic for HBV infection, HIV‐positive patients at older age and with CD4 <100 cells/μL were more likely to have isolated anti‐HBc, suggesting that compromised immunity plays a role in the presence of this marker.