Incidence of and risk factors for hepatitis B virus and hepatitis C virus infection among haemodialysis and CAPD patients: evidence for environmental transmission

Hepatitis B virus (HBV) serum markers (HBsAg, anti-HBs, anti-HBc)and antihepatitis C antibody (anti-HCV) were prospectively followedin haemodialysis and CAPD patients. From January 1987 to January1990, 185 patients on haemodialysis and 124 on CAPD were analysed.Among patients susceptible to HBV (69 on haemodialysis and 70on CAPD), there were 17 HBsAg seroconversions on haemodialysis(0.19/patient-year) and 1 on CAPD (0.01/patient-year). A Coxproportional hazards model showed that haemodialysis treatmentwas the only risk factor significantly associated with HBV infection,thus suggesting transmission through the environment. Regarding hepatitis C, 83 anti-HCV-negative patients on haemodialysisand 46 on CAPD were followed. There were 18 seroconversionson haemodialysis (0.15/patient-year) and two seroconversionson CAPD (0.03/patient-year). Haemodialysis treatment was alsothe only risk factor significantly associated with a higherrisk of HCV infection. The hazard ratio for HCV infection inhaemodialysis patients was 5.7 compared to CAPD patients. Nevertheless,for one patient on CAPD treatment transfusions were the onlypossible source of HCV infection. In conclusion, both viruses were transmitted mainly throughthe haemodialysis environment, but the role of transfusionscould not be excluded.