Hepatitis B virus infection in Haemodialysis Centres from Santa Catarina State, Southern Brazil. Predictive risk factors for infection and molecular epidemiology.
BACKGROUND
Patients under haemodialysis are considered at high risk to acquire hepatitis B virus (HBV) infection. Since few data are reported from Brazil, our aim was to assess the frequency and risk factors for HBV infection in haemodialysis patients from 22 Dialysis Centres from Santa Catarina State, south of Brazil.


METHODS
This study includes 813 patients, 149 haemodialysis workers and 772 healthy controls matched by sex and age. Serum samples were assayed for HBV markers and viraemia was detected by nested PCR. HBV was genotyped by partial S gene sequencing. Univariate and multivariate statistical analyses with stepwise logistic regression analysis were carried out to analyse the relationship between HBV infection and the characteristics of patients and their Dialysis Units.


RESULTS
Frequency of HBV infection was 10.0%, 2.7% and 2.7% among patients, haemodialysis workers and controls, respectively. Amidst patients, the most frequent HBV genotypes were A (30.6%), D (57.1%) and F (12.2%). Univariate analysis showed association between HBV infection and total time in haemodialysis, type of dialysis equipment, hygiene and sterilization of equipment, number of times reusing the dialysis lines and filters, number of patients per care-worker and current HCV infection. The logistic regression model showed that total time in haemodialysis, number of times of reusing the dialysis lines and filters, and number of patients per worker were significantly related to HBV infection.


CONCLUSIONS
Frequency of HBV infection among haemodialysis patients at Santa Catarina state is very high. The most frequent HBV genotypes were A, D and F. The risk for a patient to become HBV positive increase 1.47 times each month of haemodialysis; 1.96 times if the dialysis unit reuses the lines and filters > or = 10 times compared with haemodialysis units which reuse < 10 times; 3.42 times if the number of patients per worker is more than five. Sequence similarity among the HBV S gene from isolates of different patients pointed out to nosocomial transmission.
Carrilho
Flair J
FJ
Hepatology Branch, Department of Gastroenterology, University of São Paulo School of Medicine, São Paulo, Brazil. fjcarril@usp.br
Moraes
Cleusa R
CR
Pinho
João R R
JR
Mello
Isabel M V G C
IM
Bertolini
Dennis A
DA
Lemos
Marcílio F
MF
Moreira
Regina C
RC
Bassit
Leda C
LC
Cardoso
Rita A
RA
Ribeiro-dos-Santos
Gabriela
G
Da Silva
Luiz C
LC
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D003428:Cross Infection / Q000453:epidemiology* / Q000276:immunology / Q000821:virology; D004866:Equipment Contamination; D017743:Equipment Reuse; D005260:Female; D005838:Genotype; D006436:Hemodialysis Units, Hospital / Q000706:statistics & numerical data*; D006509:Hepatitis B / Q000453:epidemiology* / Q000276:immunology / Q000821:virology; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016133:Polymerase Chain Reaction; D006435:Renal Dialysis / Q000009:adverse effects* / Q000295:instrumentation / Q000706:statistics & numerical data; D012307:Risk Factors; D017422:Sequence Analysis, DNA; D013997:Time Factors; D000078329:Workforce
D015415:Biomarkers; D006514:Hepatitis B Surface Antigens