The U.S. Preventive Services Task Force (USPSTF) grades its recommendations (A, B, C, D, or I) and the quality of the overall evidence for a service (good, fair, poor). The definitions of these grades can be found at the end of the "Major Recommendations" field.
The USPSTF recommends against routine screening for hepatitis C virus (HCV) infection in asymptomatic adults who are not at increased risk (general population) for infection. D recommendation.
The USPSTF found good evidence that screening with available tests can detect HCV infection in the general population. The prevalence of HCV infection in the general population is low, and most who are infected do not develop cirrhosis or other major negative health outcomes. There is no evidence that screening for HCV infection leads to improved long-term health outcomes, such as decreased cirrhosis, hepatocellular cancer, or mortality. Although there is good evidence that anti-viral therapy improves intermediate outcomes, such as viremia, there is limited evidence that such treatment improves long-term health outcomes. The current treatment regimen is long and costly and is associated with a high patient dropout rate due to adverse effects. Potential harms of screening include unnecessary biopsies and labeling, although there is limited evidence to determine the magnitude of these harms. As a result, the USPSTF concluded that the potential harms of screening for HCV infection in adults who are not at increased risk for HCV infection are likely to exceed potential benefits.
The USPSTF found insufficient evidence to recommend for or against routine screening for HCV infection in adults at high risk for infection. I recommendation.
The USPSTF found no evidence that screening for HCV infection in adults at high risk (see Clinical Considerations) leads to improved long-term health outcomes, although the yield of screening would be substantially higher in a high-risk population than in an average-risk population and there is good evidence that anti-viral therapy improves intermediate outcomes, such as viremia. There is, as yet, no evidence that newer treatment regimens for HCV infection, such as pegylated interferon plus ribavirin, improve long-term health outcomes. There is limited evidence from non-U.S. studies that older therapies have some long-term health benefits for patients referred for treatment, but the generalizability of these results to the U.S. population is unknown. Of those infected with HCV, the proportion who progress to liver disease is uncertain. There is limited evidence that 10 to 20% of patients with chronic HCV infection develop cirrhosis within 20 to 30 years after infection. There is also limited evidence that available treatments are effective in preventing cirrhosis in patients with asymptomatic HCV infection. Potential harms of screening and treatment include labeling, adverse treatment effects, and unnecessary biopsies, although there is limited evidence to determine the magnitude of these harms. As a result, the USPSTF could not determine the balance of benefits and harms of screening for HCV infection in adults at increased risk for infection.
Clinical Considerations
- Established risk factors for HCV infection include current or past intravenous drug use, transfusion before 1990, dialysis, and being a child of an HCV-infected mother. Surrogate markers, such as high-risk sexual behavior (particularly sex with someone infected with HCV) and the use of illegal drugs, such as cocaine or marijuana, have also been associated with increased risk for HCV infection. The proportion of people who received blood or blood product transfusions before 1990 will continue to decline, and HCV infection will be associated mainly with intravenous drug use and, to some extent, unsafe sexual behaviors.
- Initial testing for HCV infection is typically done by enzyme immunoassay (EIA). In a population with a low prevalence of HCV infection (e.g., 2%), approximately 59% of all positive tests using the third-generation enzyme immunoassay test with 97% specificity would be false positive. As a result, confirmatory testing is recommended with the strip recombinant immunoblot assay (third-generation RIBA).
- Important predictors of progressive HCV infection include older age at acquisition; longer duration of infection; and presence of comorbid conditions, such as alcohol misuse, human immunodeficiency virus (HIV) infection, or other chronic liver disease. Asymptomatic individuals with HCV infection identified through screening may benefit from interventions designed to reduce liver injury from other causes, such as counseling to avoid alcohol misuse and immunization against hepatitis A and hepatitis B. However, there is limited evidence of the effectiveness of these interventions.
Strength of Recommendations
The USPSTF grades its recommendations according to one of 5 classifications (A, B, C, D, I) reflecting the strength of evidence and magnitude of net benefit (benefits minus harms):
A
The USPSTF strongly recommends that clinicians provide [the service] to eligible patients. The USPSTF found good evidence that [the service] improves important health outcomes and concludes that benefits substantially outweigh harms.
B
The USPSTF recommends that clinicians provide [this service] to eligible patients. The USPSTF found at least fair evidence that [the service] improves important health outcomes and concludes that benefits outweigh harms.
C
The USPSTF makes no recommendation for or against routine provision of [the service]. The USPSTF found at least fair evidence that [the service] can improve health outcomes but concludes that the balance of benefits and harms is too close to justify a general recommendation.
D
The USPSTF recommends against routinely providing [the service] to asymptomatic patients. The USPSTF found at least fair evidence that [the service] is ineffective or that harms outweigh benefits.
I
The USPSTF concludes that the evidence is insufficient to recommend for or against routinely providing [the service]. Evidence that the [service] is effective is lacking, of poor quality, or conflicting and the balance of benefits and harms cannot be determined.
Strength of Evidence
The USPSTF grades the quality of the overall evidence for a service on a 3-point scale (good, fair, poor):
Good
Evidence includes consistent results from well-designed, well-conducted studies in representative populations that directly assess effects on health outcomes.
Fair
Evidence is sufficient to determine effects on health outcomes, but the strength of the evidence is limited by the number, quality, or consistency of the individual studies, generalizability to routine practice, or indirect nature of the evidence on health outcomes.
Poor
Evidence is insufficient to assess the effects on health outcomes because of limited number or power of studies, important flaws in their design or conduct, gaps in the chain of evidence, or lack of information on important health outcomes.
