Hepatitis C virus (HCV) may be a cause of hematologic malignancies and thyroid cancer. HCV infection is common among U.S. military veterans receiving care in the Veterans Administration healthcare system. The investigators propose a retrospective cohort study using VA administrative databases. A cohort of approximately 147,000 HCV-infected veterans has been identified for the period 1997-2004. Likewise, a cohort of approximately 573,000 HCV-uninfected veterans has been identified for the same period. These subjects are being evaluated for the diagnosis of hematologic malignancies, thyroid cancer, and related medical conditions as recorded in VA databases. The comparison of the prevalence and incidence of these cancers in the two cohorts will provide a test of the hypothesis that HCV infection can cause these cancers.
The investigators will also evaluate the association between HCV infection and several other medical conditions, which might be related to HCV infection, specifically: immune thrombocytopenic purpura, autoimmune hemolytic anemia, cholangiocarcinoma, cholangitis, and pancreatic cancer.
