Changing serum levels of quantitative hepatitis B surface antigen and hepatitis B virus DNA in hepatitis B virus surface antigen carriers: a follow-up study of an elderly cohort.

This study was to elucidate longitudinally quantitative changes of hepatitis B virus (HBV) surface antigen (HBsAg) and HBV DNA in elder HBsAg carriers in a community. Among 1002 residents screened for HBsAg in 2005, 405 responded to this follow-up study in 2010. Fifty-nine (14.6%) were HBsAg carriers in 2005; HBsAg quantification and HBV DNA were measured. HBsAg quantification (cutoff 1600 IU/mL) and HBV DNA (cutoff 2000 IU/mL) were combined to stratify the participants between two screens. A total of 30 men and 29 women with a mean age of 63.9 ± 7.9 years were enrolled. Quantitative levels of HBsAg and HBV DNA were significantly correlated in 2005 (r = 0.509, p < 0.001) and 2010 (r = 0.777, p < 0.001). Concentrations of HBsAg (IU/mL) significantly decreased from 2.2 ± 1.0 log in 2005 to 1.7 ± 1.5 log in 2010 (p < 0.001). The level of HBsAg was decreased in 48 (81.4%) individuals and HBsAg was undetectable in eight (13.6%). The annual incidence of HBsAg clearance was 2.7%. These 59 HBsAg carriers in 2005 were divided into four groups: low HBsAg low HBV DNA (n = 32), high HBsAg low HBV DNA (n = 5), low HBsAg high HBV DNA (n = 12) and high HBsAg high HBV DNA (n = 10). All 32 individuals in the low HBsAg low HBV DNA group were still in that group in 2010, whereas only two of the high HBsAg high HBV DNA group became inactive. As with a younger cohort in hospital, HBsAg quantification was still well correlated with HBV DNA in elderly HBsAg carriers in the community. Lower levels of both HBsAg and HBV DNA might represent an inactive HBV infection.