Hepatitis B vaccination in haemodialysis patients: an underestimated problem. Factors influencing immune responses in ten years of observation in an Italian haemodialysis centre and literature review.

Objectives. Despite universal infection control precautions, the risk of hepatitis B virus (HBV) infection in patients on chronic haemodialysis (HD) remains high. For this reason anti- HBV vaccination is recommended in these subjects. In hemodialyzed patients vaccinal response is often suboptimal and it's not clear what factors may influence it. Study design. The aim of our study is to assess the influence of some clinical and laboratory factors on seroconversion rate after anti HBV vaccination in a cohort of patients on maintenance HD. Methods. We analysed 60 patients on regular HD, 40 men and 20 women (age 64 +/- 12 years, range 40-88 years), immunized with Engerix B (R) vaccine, followed for an average time of 62 month (12-120 months). For each patient the following data were collected: age, serum albumin (sAlb), Blood urea nitrogen before HD session (BUN), age at vaccination, dialysis vintage, presence of systemic disease, type of vascular access, dialysis modality. Correlation between these factors and anti Hbs titer was estimated with multiple regression analysis. Results. Anti-Hbs seroconversion rate (Anti Hbs > 10 IU/l) was 77%. Better rate of seroconversion (86%) was observed in patients with arteriovenous fistula (AVF) and serum albumin > 3,5 g/dL (93%), while higher rate of not responders (50%) in patients with systemic diseases. The only parameter correlated to anti Hbs titer was sAlb (p = 0,0012). sAlb was correlated to age in all patients (p=0,01) and age was correlated to higher anti Hbs titer in the responder group (p=0,018). Discussion. In our experience an early vaccination, when patients on chronic HD are younger and in better nutritional conditions, improves anti-HBV response.