The principal goal of this research project is to evaluate the natural history of HCV and liver disease and its treatment in HIV-infected persons who use drugs. Research procedures will focus on determining liver disease prevalence and severity within this population. This is an observational study without study specific interventions.

The principal goal of this research project is to evaluate the natural history of HCV and liver disease and its treatment in HIV-infected persons who use drugs. The recent availability of a novel, non-invasive method of measuring HCV disease stage makes it possible to test the relationship of HCV disease stage and the management of coinfected IDUs with adequate precision. The investigators will apply the innovative technology, elastography (FibroScan®) to ask whether the marked differences in the final disease outcome, end-stage liver disease (ESLD), can be explained by a measure of liver stiffness as assessed by elastography (FibroScan®). While advances in non-invasive disease assessment are critical to HCV management, the greatest challenge to improving HCV treatment effectiveness in coinfected persons remains low rates of treatment uptake and adherence, even when freely accessible. In response to this glaring disparity, the investigators will test potent behavioral reinforcement interventions to improve the management of HCV disease by adapting a rigorously studied contingent behavioral incentives program to the treatment to coinfected IDUs. Hepatitis C Treatment Eligibility: To determine the population prevalence of significant liver disease in coinfected IDUs using an innovative, non-invasive methodology (transient elastography, FibroScan®) to measure liver stiffness. Liver Disease Staging: To test the hypothesis that liver stiffness, assessed by a novel, non-invasive methodology, is predictive of the development of ESLD, defined as hepatic decompensation, hepatocellular cancer, and liver-related death, in coinfected IDUs.

Inclusion Criteria:

• Current or prior drug use
• Reactive HCV antibody
• Reactive HIV antibody

Exclusion Criteria:

• Women may not undergo FibroScan while pregnant
• Persons with implanted cardiac devices may not undergo FibroScan

This is a prospective observational cohort of HIV-infected persons receiving medical care at the Johns Hopkins Hospital. Participants are eligible if they are HCV antibody positive and use or have used drugs.