Chronic liver disease mortality attributable to hepatitis B and C in New Zealand

This research aimed to estimate the prevalence and population attributable risk percent (PAR%) of hepatitis B (HBV) and C (HCV) infection among chronic liver disease (CLD) deaths in New Zealand. The PAR% is the percentage of CLD cases attributable to either HBV or HCV. Within New Zealand, there are large differences in HBV prevalence by ethnic group, so prevalence and PAR% estimates were made separately for the three major ethnic groups.

The study sample was selected from CLD deaths between 1992 and 1997. Data were extracted from hospital records and coroners' reports. The prevalence and PAR% of HBV and HCV were estimated.

Data were extracted for 303 of 359 decedents selected for inclusion. Hepatitis B virus and HCV test results were identified in 67 and 43%, respectively. Among those cases tested, the prevalence (and estimated PAR%) of HBV infection was 68% (PAR% 66%) for Pacific people, 54% (PAR% 52%) for Maori and 10% (PAR% 10%) for European New Zealanders. The prevalence (and estimated PAR%) of past or present HCV infection ranged between 8 and 15% (PAR% 8-14%) for the three major ethnic groups.

The present study has demonstrated that HBV and HCV infections are important contributors to CLD mortality in New Zealand. With the introduction of universal hepatitis B vaccination in the late 1980s, we would expect the burden of CLD deaths attributable to HBV to decrease in the future. However, the burden of CLD deaths due to HCV is likely to increase.