Chronic hepatitis B virus infection in south Auckland

Previous studies have identified high prevalence rates of hepatitis B infection in New Zealand Maori, Pacific Island and Asian populations within New Zealand. However, the true impact of chronic hepatitis B virus (HBV) infection on health resources has not been evaluated. This study was designed to determine the incidence of serious sequelae of chronic HBV infection in a high prevalence community.

All patients treated for HBV-related conditions at Middlemore Hospital from January 1995 to January 1997 were identified through discharge coding and laboratory records. Demographic characteristics and laboratory results, including liver function tests, hepatitis serology and liver histology were recorded. Number of admissions, average length of stay and survival were calculated from Casemix data.

During the study period, 215 patients were referred for management of hepatitis B infection, of whom 179 had persistently elevated aminotransferases. Forty six percent of patients were hepatitis B 'e' antigen (HBeAg) negative, and 21% of these had delta co-infection (all Samoan). Liver biopsy was performed in 87 patients with raised aminotransferases. No features of chronic hepatitis were found in 5%, mild chronic hepatitis in 30%, moderate to severe chronic hepatitis in 44% and cirrhosis in 22%. Fifty five patients were admitted to hospital during the two year period with an HBV-related diagnosis, with an average length of stay of 12.2 days compared to 4.9 days for all other medical and surgical admissions during this period (p < 0.001). Twenty eight of the 55 subsequently died, 20 from hepatocellular carcinoma.

Chronic hepatitis B infection is associated with significant morbidity and mortality in Maori, Pacific Islanders and Asians living in South Auckland. Screening of these high risk populations with vaccination of noninfected individuals should reduce the incidence of these serious sequelae and eventually lead to eradication of HBV.