Occult hepatitis B among patients with chronic renal failure on hemodialysis from a capital city in northeast Brazil.

Occult hepatitis B (OHB) is characterized by the presence of HBV-DNA in the absence of HBsAg in the serum of patients. Hemodialysis patients are at high risk for hepatitis B virus and there are few data on the prevalence of OHB in this population, mainly in Brazil. Thus, the aim of this study was to determine the prevalence of OHB in patients undergoing hemodialysis. A cross-sectional study was performed, including 301 patients on chronic hemodialysis at two dialysis centers in São Luís (Maranhão), northeast Brazil. Serological tests were performed for HBsAg, anti-HBc, anti-HBs, and anti-HCV using enzyme immunoassays (ELISA); HBV-DNA and HCV-RNA were studied by real-time PCR. The mean age was 49 ± 15 years, and 128 (42%) were female. Serological tests confirmed that all samples were HBsAg negative. Anti-HBc was positive in 114 (38%) patients, anti-HBc and anti-HBs were simultaneously positive in 104 (35%), and anti-HBc alone was positive in 10 (3%). Tests were negative for anti-HBc and anti-HBs in 55 patients (18%). Anti-HBs was the only positive marker in 132 (44%) patients. Anti-HCV was positive in 15 (5%) patients with HCV-RNA present in 14 of them (93%). HBV-DNA was positive in seven cases (2.3%). There was no association of HBV-DNA with age, gender, time on dialysis, previous kidney transplant, or HBV serological pattern, but there was a positive correlation with the presence of anti-HCV (P < 0.001). OHB in chronic renal failure patients on hemodialysis appears to be a relevant finding, suggesting that studying HBV-DNA in this population using sensitive molecular tests should be a recommended course of action, especially in candidates for renal transplant.