Hepatitis C virus infection in cocaine users--a silent epidemic.

Over a recent three year period, approximately 600 individuals responded to newspaper advertisements for research studies requiring healthy, cocaine using subjects. These subjects were screened using a standard phone interview in order to eliminate individuals with known medical or psychiatric illnesses that would exclude them from ongoing neuroimaging studies of drug abuse. Individuals were specifically asked about their hepatitis and HIV status. Of these, 170 subjects passed the phone screen, having no known medical or psychiatric illness outside of cocaine abuse/dependence and were willing to be further evaluated for the studies. These subjects were brought to the Medical College of Wisconsin's General Clinical Research Center and tested for, among other measures, hepatitis B, hepatitis C, and HIV. Of these, 144 completed the examination and all testing. In this cohort of assumed healthy subjects, 47 (33%) tested positive for antibodies to the hepatitis C virus (HCV). Only 7 (5%) tested positive for the hepatitis B surface antigen and 2 (1.4%) to HIV. The demographics of this cohort are 56% African-American, 81% male, 75% never-married, 55% unemployed with a mean age of 36 years. The percentage of subjects reporting any lifetime intravenous drug use among the HCV(+) and the HCV(-) cohorts was 77% vs. 29% respectively. Some routes of HCV transmission are still unclear and may reflect lifestyle or other factors related to cocaine use outside of parenteral drug use. Since almost all HCV infections become chronic, and many progress to chronic active hepatitis, cirrhosis, and ultimately hepatocellular carcinoma, these observations suggest a significant epidemic in an unsuspecting population with little regular access to health care. These individuals also form a large pool for the continued transmission of HCV to the general population. Additional public health interventions are suggested.