Hepatitis C Targeted Screening Misses Many Cases

Ricki Lewis, PhD

November 26, 2012

In 2004 the United States Preventive Services Task Force (USPSTF) recommended against routine screening for hepatitis C virus (HCV) infection in asymptomatic adults not at increased risk. Now, an updated review, including studies published through May 2012, indicates that targeted screening can miss up to two thirds of infected patients. However, wider nontargeted screening is unlikely to alter clinical outcomes, the reviewers report in an analysis published online November 26 in the Annals of Internal Medicine.

Roger Chou, MD, from the Oregon Health & Science University in Portland, and colleagues consulted case-control, cross-sectional, and randomized studies assessing clinical outcomes after screening, as well as investigations of harms from screening.

The USPSTF did not advise routine screening in 2004 because evidence did not support either screening or not screening individuals without liver enzyme abnormalities or other risk factors. In addition, USPSTF advised against screening because although tests are accurate and treatments lower viremia, people without risk factors are unlikely to become infected, and if they do, long-term progression is rare. There was no evidence that screening could reduce transmission or improve health outcomes.

However, in 2012, the Centers for Disease Control and Prevention recommended screening everyone born between 1945 and 1965, as two thirds of people with HCV infection were born during these years. Up to 75% of infected individuals do not know they are infected.

In the current review, Dr. Chou and colleagues probed studies from databases, clinical trial registries, and reference lists, asking:

  • Does screening reduce HCV-associated morbidity and mortality, affect quality of life, or lower incidence of infection?

  • Does screening's effect on clinical outcomes differ using different screening criteria?

  • What are the sensitivity and number needed to screen to identify a single case of infection, using risk- or prevalence-based methods?

  • What harms may result from screening?

The report cites individual study results. For example, a cross-sectional study screened 3367 patients in a sexually transmitted infection clinic for 5 risk factors and identified infection with a sensitivity of 97% and with 13 patients needed to be screened to detect a single infection.

Overall, they found that screening accurately identifies infection and is associated with minimal risk. However, nontargeted screening does not alter clinical outcomes (mortality, end-stage liver disease, cirrhosis, liver cancer, quality of life, need for transplant, transmission, and harms associated with screening or liver biopsy).

"Retrospective studies found that screening strategies targeting multiple risk factors were associated with sensitivities exceeding 90% and numbers needed to screen to identify 1 case of HCV infection of less than 20," the authors write. However, studies of more narrowly targeted populations missed up to two thirds of infected patients.

Limitations include reliance on a few large retrospective studies, none of which compared clinical outcomes between a screened and nonscreened group or compared different screening criteria. The researchers call for "[c]linical studies that prospectively evaluate the accuracy, yield, and outcomes of alternative HCV screening strategies."

The USPTF plans to update its HCV screening recommendations after considering the current report and a separate review on antiviral treatments.

The authors have disclosed no relevant financial relationships.

Ann Intern Med. Published online November 26, 2012.