Hepatitis C virus (HCV) testing and diagnosis rates in the commercially insured and Medicare populations in the U.S

Introduction: Hepatitis C virus (HCV) infection is the most common blood-borne disease in the U.S., with an estimated 4.1 million individuals (1.6% of the population) testing positive for anti-HCV antibodies. Chronic HCV infection may lead to liver failure, hepatocellular carcinoma, and liver transplant. However, ~75% of infected patients remain undiagnosed.

Methods: To study the relationship between U.S. testing and diagnosis trends, we analyzed the 2004-2008 Thompson MedStat Marketscan and the Medicare 5% sample databases. Patients tested were identified using outpatient claim and CPT codes for diagnostic tests. Medical claims were analyzed to identify testing outcome using ICD-9 codes. For the commercially insured population, the percentage being treated following diagnosis was identified using HCPCS/NDC codes.

Results: Annual HCV testing rates for commercial and Medicare populations were 1.1% and 1.7%, respectively, and 2% and 9% of the tested population was diagnosed, respectively. HCV testing was more common among younger patients among whom HCV prevalence is low, and less common among “baby boomers” (1946-1964), who account for up to two-thirds of the HCV-infected population. Overall, 19% of the commercially insured population received treatment within one year following initial diagnosis.

Conclusions: HCV testing rates in the commercially insured and Medicare populations were low in 2004-2008 in the U.S. These findings may partially explain the high percentage of undiagnosed patients. Treatment within one year following diagnosis was 19% in the commercially insured population. Further studies are needed to explore other potential causes for low testing and diagnosis rates in the U.S.