Interferon-based therapies for hepatitis C: Utilization, costs, and outcomes

Background: Veterans using the Veterans Health Administration's (VA's) services have a higher incidence of chronic hepatitis C virus (HCV) infection than the general population. Objectives: To examine treatment patterns, direct costs associated with interferon-based HCV therapy, and sustained virologic response (SVR) rates for genotypes 1 and 2. Study Design: Retrospective review of utilization, cost, and outcome data for a cohort of 99 consecutive patients diagnosed with HCV receiving antiviral therapy beginning in January 2000 at a midwestern VA Medical Center. Methods: Outpatient utilization and direct costs of clinical encounters and medications spanning calendar years 1997 to 2004 were extracted from VA administrative databases for 3 therapy combinations: interferon and ribavirin (IR); interferon, pegylated interferon, and ribavirin; and pegylated interferon and ribavirin (PR). Final costs were adjusted to 2010 prices. Identifying patients' earliest diagnostic dates ensured analyses of treatmentnaïve patients. Results: Clinic visits and medications accounted for 20% and 80% of treatment costs respectively, regardless of genotype. Although genotype 1 patients' treatment length and costs were substantially higher than those of non-genotype 1 patients, SVR rates were lower (31%) than those in non-genotype 1 patients (57%). Cost per SVR for genotype 1 patients ranged from $54,768 (IR) to $70,364 (PR). The overall cost per SVR for non-genotype 1 patients was $25,152. Conclusions: Antiviral medications accounted for the majority of treatment costs. Cost per SVR was sensitive to genotype, effi cacy, and treatment duration. Utilization, costs, and outcomes associated with interferon-based treatments serve as important baseline data for future comparative cost-effectiveness analyses.