Incidence and risk factors for hepatitis C seroconversion in hemodialysis: A prospective study

Abstract

To delineate the incidence and risk factors for seroconversion (SC) for HCV, from May 1991 to November 1992 we followed all 401 patients (no i.v. drug abusers) dialyzed in 15 Belgian hemodialysis (HD) units, none of which isolates anti-HCV (+) patients. The sensitive ELISA II test was performed in the same laboratory for all patients. ELISA II (+) sera were considered truly positive if specific antibodies were detected by RIBA II against at least one HCV antigen. Blood transfusions given from 12 months prior to inclusion in the study, dialyzer reuse and frequency of dialysis monitor sterilization were recorded. In May 1991, prevalence of truly positive ELISA II tests averaged 13.5% (54/399). During the three consecutive six-month periods, ELISA II became truly positive in 3 of 305 (1%), 4 of 314 (1.3%) and 1 of 313 (0.3%) patients, respectively, which was an average yearly incidence of 1.7%. SC was preceded (1 to 6 months) in all cases by an unexplained, unprecedented increase in the alanine aminotransferase level. The mean monthly rate of transfusions was significantly higher (P < 0.001) in eight patients with SC (0.7 ± 0.6 U) than in 393 patients without SC (0.1 ± 0.01 U). However, three of eight patients with SC had not been transfused at all. SC was observed in only 3 of 13 units (1, 3 and 4 cases, respectively) dialyzing ELISA (+) patients. In the unit with three SC, patients were always assigned a fixed station: SC was observed only in patients dialyzed next to an ELISA II (+) patient (3 of 8 vs. 0 of 30, P < 0.02). These facts suggest nosocomial transmission. SC was not associated with dialyzer reuse or the lack of sterilization of the dialysis monitor after each session. In conclusion, the yearly incidence of SC (ELISA II) averaged 1.7% in our group of hemodialyzed patients. Contamination appeared to be both transfusional and nosocomial. The absence of SC in 10 of 13 units dialyzing ELISA (+) patients suggests that isolation of such patients is not yet warranted. Strict adhesion to the 'universal precautions' (CDC, Atlanta) is probably sufficient to prevent nosocomial transmission. Further long-term studies are needed to confirm these conclusions.