Assessment of chronic hepatitis B: the importance of hepatitis B virus DNA testing

BACKGROUND: Chronic hepatitis B (CHB) has an estimated prevalence of 90 000 to 160 000 in Australia. Cirrhosis and hepatocellular carcinoma are important complications of CHB and appropriate evaluation of hepatitis B surface antigen (HBsAg)-positive individuals is vital to identify treatment candidates. METHODS: A review of the database of a tertiary hospital was performed and 348 HBsAg-positive individuals with baseline demographic, virological, serological and biochemical variables were identified and evaluated cross-sectionally. A small subgroup of hepatitis B e antigen (HBeAg)-negative patients with normal alanine aminotransferase (ALT) at baseline were identified and followed longitudinally. RESULTS: 175/348 (50%) of patients were in the HBeAg-negative, chronic hepatitis phase of disease, 22% in the HBeAg-positive immune clearance and 6% in the immune tolerant phases. HBeAg-negative patients were older and more likely to be male than HBeAg-positive patients. The correlation between hepatitis B virus (HBV) DNA and ALT levels was examined. ALT and HBV DNA levels showed no correlation in HBeAg-positive CHB and only a weak correlation in HBeAg-negative patients. Furthermore, 35% of HBeAg-negative patients with detectable HBV DNA had a normal ALT. Conversely 38% of HBeAg-negative patients with no detectable HBV DNA had an elevated ALT. A persistently normal ALT over 24 months was seen in five of nine HBeAg-negative patients with normal initial ALT and detectable HBV DNA. CONCLUSION: Appropriate evaluation of HBeAg-negative CHB must include HBV DNA because the ALT is not a reliable guide to underlying viral replication.