Model of Life Expectancy of Chronic Hepatitis B Carriers in an Endemic Region

BACKGROUND Chronic infection with hepatitis B (HBV) is a known risk factor for increased mortality from hepatocellular carcinoma (HCC) and chronic liver disease (CLD). However, the specific effects of chronic HBV infection on life expectancy have not been adequately studied. Taiwan is endemic for HBV infection, and thus provides sufficient information for such estimates. METHODS Population mortality statistics, combined with data on the contribution of HBV to HCC and CLD deaths, were used to model carrier mortality by sex and e antigen status. An abridged life table was used to calculate carrier life expectancy. RESULTS Among both males and females, those who are e antigen-positive are more likely to die from HCC than from CLD. When e antigen status remains positive, absolute liver mortality rates climb significantly after age 40 years. CLD is a proportionally higher threat for e antigen-negative females than for other subgroups. Males have higher liver-related mortality at all ages. A small decrease in life expectancy, from 82.0 to 80.1 years, was found for female noncarriers versus female carriers; a larger discrepancy was observed for males-from 76.2 to 71.8 years. In comparison to noncarriers, the lifetime relative risk of mortality is 1.35 for male carriers and 1.16 for female carriers. CONCLUSIONS These results indicate that chronic HBV infection results in significant liver-related mortality; however, carriers retain a satisfactory life expectancy.