Determining rates of hepatitis C in a clozapine treated cohort

ObjectiveTo determine the prevalence rates of hepatitis C in patients with schizophrenia and schizoaffective disorder being treated with clozapine.MethodsClozapine-treated outpatients and inpatients were recruited from the Centre for Addiction and Mental Health Schizophrenia Program in Toronto, Canada. All subjects had liver function tests, and positive HCV status was defined as a positive qualitative HCV RNA assay. Subjects completed a self-report questionnaire assessing HCV risk factors, past history of liver disease, previous diagnosis of human immunodeficiency virus (HIV), past hepatitis B virus (HBV) infection and current alcohol use.Results110 subjects participated in the study and the HCV prevalence rate (antibody and viremia-positive) was 2.7%, compared to a 0.8% prevalence rate in Canada. All study subjects had established housing, none reported a history of HIV, and only one patient had a history of HBV infection. A total of 9% drank two or more drinks on a typical day drinking and 7% endorsed having six or more drinks on one occasion at least monthly. Two of 3 HCV-viremia positive subjects had HCV risk factors, specifically intravenous drug use and intranasal cocaine use. There was no difference between HCV infected and HCV negative subjects on liver function tests.ConclusionsOur study demonstrates elevated rates of HCV in clozapine-treated patients compared to the general population in Canada and are congruent with reports from United States centres. Our study highlights the importance of homelessness and patterns of high-risk behaviour when interpreting HCV prevalence rates in this sub-population of patients and should be explored in future studies.