Seroconversion rate to positivity for antibodies against core antigen of hepatitis B virus and duration of renal replacement therapy.

BACKGROUND Prevalence of total antibodies against core antigen (anti-HBc) of hepatitis B virus (HBV) is greater in longer dialysed patients, but there are no data indicating a relationship between the higher seroconversion rate to anti-HBc positivity and longer renal replacement therapy (RRT) vintage prior to seroconversion. Our aim was to evaluate the association between RRT duration and seroconversion to anti-HBc positivity. METHODS An incidence of anti-HBc was evaluated in 425 anti-HBc-negative intermittent haemodialysis (IHD) patients: Group I included patients who underwent first anti-HBc testing 31 days from first IHD session, and Group II or III included patients with RRT duration < 3 or ≥ 3 years, respectively. Anti-HBc testing was repeated every 6-12 months. Sex, age, RRT duration, anti-HCV, HCV RNA, ALT, ASP, GGT, full vaccination series against HBV with developed anti-HBs titre > 10 IU/L, hepatitis history and underlying kidney diseases were used as independent variables predicting seroconversion to anti-HBc positivity. RESULTS Seroconversion rate to anti-HBc positivity was 2.59, 2.12 and 2.44 episodes/100 patient-years in Group I (n = 174), II (n = 170) and III (n = 80), respectively. In the entire group, there were 15 seroconversions to anti-HBc and one seroconversion to HBsAg positivity. The only variable predicting seroconversion in all HBsAg-negative patients (n = 424) was the lack of full vaccination series against HBV with developed anti-HBs titre > 10 IU/L maintained during the study (β - 0.112, P = 0.04). CONCLUSIONS Seroconversion rate to anti-HBc positivity is not related to duration of RRT treatment but to ineffective vaccination against HBV.