The United States Preventive Services Task Force (USPSTF) concludes that there is not enough evidence to recommend routine screening for hepatitis C virus (HCV) infection, according to a new guidelines statement published in the March 16th issue of the Annals of Internal Medicine.
HCV infection rates in the US general population are low (estimated at about 2%), but rates are significantly higher among individuals with known risk factors, including those who received a blood transfusion prior to 1990, those who sustained an occupational exposure such as a needle-stick, and injection drug users (among whom the infection rate may reach as high as 90%). Whilst some 75% of exposed individuals develop chronic infection (50%-85% in various studies), only about 10-20% of these progress to severe liver damage (cirrhosis, liver cancer, or end-stage liver disease), usually over a period of 10-30 years. Predictors of progression include older age at the time of infection, longer duration of infection, and heavy alcohol use. Studies also suggest that individuals coinfected with both HCV and HIV are more likely to experience rapid progression to severe liver disease.
Although antibody tests can accurately identify people infected with HCV, it is not clear whether routine screening is cost-effective or confers long-term benefits. After reviewing available data, the USPSTF determined that, for low-risk individuals, “There is no evidence that screening for HCV infection leads to improved long-term health outcomes, such as decreased cirrhosis, hepatocellular cancer, or mortality.” In addition, the potential harms of widespread screening of low-risk adults, including anxiety, possible biopsy complications, and the side-effects and cost of treatment are “likely to exceed potential benefits”, the panel concluded. Therefore, the USPSTF recommends against routine HCV screening for individuals with no symptoms of liver disease who are not at increased risk for infection.
More controversially, the task force also declined to take a position either for or against screening of adults with specific risk factors for HCV infection. The panel “found no evidence that screening for HCV infection in adults at high risk leads to improved long-term health outcomes,” and “could not determine the balance of benefits and harms of screening for HCV infection in adults at increased risk for infection.”
The USPSTF also suggested that there are not enough data to assess the long-term benefits of hepatitis C treatment. Whilst “there is good evidence that antiviral therapy improves intermediate outcomes, such as viremia [HCV viral load],” the task force concluded, “[t]here is, as yet, no evidence that newer treatment regimens for HCV infection, such as pegylated interferon plus ribavirin, improve long-term health outcomes.” In particular, the value of treatment for otherwise healthy, asymptomatic individuals remains unclear.
In contrast to the USPSTF, the US National Institutes of Health and the Centers for Disease Control and Prevention (CDC) both recommend screening for high-risk individuals such as injection drug users, pre-1990 transfusion recipients, people with multiple sexual partners, children born to HCV-infected mothers, and people with persistently elevated liver enzyme (ALT) levels.
After the USPSTF recommendations appeared, both the American Association for the Study of Liver Diseases (AASLD) (click here for statement) and the American Liver Foundation (click here for statement ) released statements expressing concern. Conclusive evidence for the benefits of hepatitis C screening and treatment is lacking because the disease takes so long to progress. HCV was only identified 15 years ago, and current therapies have been under study for less than a decade. “Researchers will not be able to determine the benefits and harms of screening unless there is screening of high-risk populations,” said AASLD president Bruce Bacon, MD. “To misinterpret the [USPSTF] report to say that such screening should be stopped would be a terrible mistake with grave consequences over the next two decades.”
References
The USPSTF recommendation statement, an accompanying journal article, and the complete information upon which the recommendations were based are available here.
U.S. Preventive Services Task Force. Screening for hepatitis C virus infection in adults: recommendation statement. Annals of Internal Medicine 140 (6): 462-464, March 16, 2004.
Chou R et al. Screening for hepatitis C virus infection: a review of the evidence for the U.S. Preventive Services Task Force. Annals of Internal Medicine 140 (6): 465-479, March 16, 2004.
National Institutes of Health Consensus Development Panel. Management of Hepatitis C. 2002.
CDC. Recommendations for Prevention and Control of Hepatitis C Virus (HCV) Infection and HCV-Related Chronic Disease. Morbidity and Mortality Weekly Report 47 (RR-19). October 16, 1998.