Epidemiology and clinical outcomes of hepatitis delta (D) virus infection in Queensland, Australia.

OBJECTIVES: To investigate the epidemiology, clinical characteristics and outcomes of those with hepatitis delta virus (HDV) infection in Queensland, Australia.

DESIGN: Retrospective cohort study of individuals tested for HDV between 1997 and 2016 in the public healthcare system in Queensland.

RESULTS: 179 individuals recorded positive HDV serology between 1997 and 2016, with a total of 4407 individuals undergoing testing (seroprevalence 4.1%). The majority of HDV positive individuals were male and were born overseas. Those born in Africa had a higher risk ratio (RR) for HDV infection (RR, 1.55; 95% CI, 1.14-2.09); being born in Asia was associated with a relatively lower risk of HDV infection (RR, 0.36; 95% CI, 0.27-0.58). Positive hepatitis C virus (HCV) serology was significantly associated with positive HDV serology (RR, 2.98; 95% CI, 2.36-3.78). Of the HDV positive individuals born in Australia, the majority were HCV positive (69.8%). HDV positive individuals were less likely to be Hepatitis B e antigen (HBeAg) positive (RR, 0.64; 95% CI, 0.45-0.93) and recorded lower hepatitis B virus (HBV) viral loads. Positive HDV serology was associated with increased risk of liver cirrhosis (RR, 2.3; 95% CI 1.73-3.07) and liver transplantation (RR, 1.93; CI 1.31-2.85). Only 8% of HDV positive individuals underwent HDV treatment.

CONCLUSIONS: In Queensland, HDV seropositivity is associated with overseas birth, particularly in Africa. HDV infection is associated with decreased HBV viraemia and more advanced liver disease.