P1456PREVALENCE OF HEPATITIS B CORE ANTIBODY AND OCCULT INFECTION AMONG HAEMODIALYSIS PATIENTS
Authors: Mooppil Nandakumar , Aithal Seema , Ibakkanavar Rajiva , Singh Tripti 
Published: June 2020

Abstract

Background and Aims
Haemodialysis (HD) patients are highly susceptible to blood borne virus infections and prevention strategies include surveillance, segregation, vaccination and strict implementation of standard precautions. As per new guidelines it is mandatory for all HD patients to be tested for hepatitis B core antibody at the beginning of renal replacement therapy. In the present study we sought to determine the prevalence of core antibody positivity and occult HBV infection as evidenced by viraemia in hepatitis B surface antigen (HBsAg) negative patients on maintenance haemodialysis.

Method
All HD patients (aged≥ 18 years) who were dialyzing in 2019 were included in this cross-sectional study. Retrospective data based on one-off screening for hepatitis B core antibody total (anti-HBc) for all HBsAg negative patients (study population) carried out between May and Oct 2019 was used for analysis. Information was gathered on HBsAg, anti-HBc antibody, surface antibody (anti-HBs) and Hepatitis B virus (HBV) DNA. All anti-HBc antibody positive patients were tested for HBV DNA using quantitative PCR assay. Patients were classified as immune (anti-HBs &gt;10 IU/L) and non-immune (anti-HBs ≤10 IU/L) based on surface antibody levels. Demographic data were compared using Chi square test for categorical variables and Independent T test/Mann Whitney U test for continuous variables between the patients with and without HBV core antibody. Baseline characteristics were compared between the immune and non-immune groups using Chi square test and Independent T test/Mann Whitney U test as appropriate.

Results
A total of 3704 HBsAg negative HD patients (mean age 63.5±11.3 years, 56.1% male, 57.7% Chinese, 65.4% diabetic and mean vintage of 5.8±5.4 years) were included in the study after exclusion of 147 patients (3.8%) who had chronic HBV infection from the entire HD cohort of 3851 patients. 895 (24.2%) showed evidence of past HBV infection (anti-HBc positive but HBsAg negative) with only 3 (0.1%) patients having detectable HBV DNA. The HBV core antibody positive patients were predominantly elderly, Chinese, males and with high medical dependency compared to the patients without HBV core antibodies (p&lt;0.001). There were no statistically significant differences in diabetic status and dialysis vintage between the patients with and without HBV core antibody. 3202 (86.4%) patients were immune following vaccination (anti-HBs &gt;10 IU/L). The non-immune patients (13.5%) were more likely to be diabetic, with high medical dependency and lower vintage compared to immune patients (p&lt;0.001). Age, race and gender did not differ significantly between the immune and non-immune patients.

Conclusion
The prevalence of hepatitis B core antibody positivity was 24.2% in our large racially diverse haemodialysis cohort but the presence of occult HBV was low (0.1%). Elderly Chinese males with high comorbidity and poor functional status were more likely to have evidence of past HBV infection. Occult HBV infection has implications in policy development for the prevention of HBV infection in dialysis centres.