A Case-Control Study on Occult Hepatitis B Infection in Chronic Hemodialysis Patients from South-West of Iran

Blood born viral infections such as hepatitis B virus (HBV) are major concerns in chronic hemodialysis (CHD) patients and hemodialysis units. Undetected HBs Ag in the presence of viral DNA، occult HBV infection (OBI)، is a concern in the care of CHD patients and hemodialysis unit as a mode of transmission. In this case-control study we compare the frequency of OBI in the CHD patients with the normal population. 82 consecutive CHD patients and 82 healthy individuals without any risk factors for HBV infection were enrolled in this study. A selection criterion was negative serum HBs Ag by ELISA method. Subsequently، the sera were tested for HBV DNA by nested PCR method. In the CHD group، 55 (67. 1%) were male and 27 (32. 9%) were female، with the overall mean age of 54. 32 ± 13. 67 years old. The mean age of control group was 32. 65 ± 8. 51 years old، with 26 (31. 7%) male and 56 female (69. 3%). HBV DNA was present in 9 (11%) CHD patients، 4 (8%) of whom were seronegative for anti-HBc and anti-HBs antibodies. No HBV DNA was identified in the control group (p<0. 0001). History of blood transfusion was present in all OBI CHD patients and 59 (80. 9%) of non-OBI CHD patients. Duration of hemodialysis in OBI CHD and non-OBI CHD patients were 73. 56 ± 39. 53 and 44. 24 ± 24. 59 months، respectively (p =0. 002). The prevalence of occult HBV infection is relatively high in patients with chronic hemodialysis in our region. Duration of hemodialysis and history of blood transfusion are important risk factor for OBI infection. A more sensitive method، such as PCR، may need to be considered in this patient population.