Thursday, August 16, 2012

Screening for hepatitis C in Baby Boomers

- Kenny Lin, MD

Today, the Centers for Disease Control and Prevention finalized new recommendations for one-time screening for the hepatitis C virus (HCV) in all persons born between 1945 and 1965, a generation better known as the "Baby Boomers." The CDC's new recommendations are published in the Annals of Internal Medicine. Previously, the CDC only recommended that persons with behavioral or medical risk factors for HCV be routinely tested. The rationale for expanded screening in persons age 47 to 67 is that more than 75% of persons with antibodies to HCV (demonstrating evidence of prior infection) belong to this age group,  due to a higher prevalence of injection drug use. Since more than half of adults with HCV are unaware that they are infected, the CDC recently estimated that routine screening and treatment of infected persons in this "birth cohort" would be cost-effective.

It remains unclear what impact the new CDC recommendations will have on primary care, given that the American Academy of Family Physicians continues to follow the U.S. Preventive Services Task Force's 2004 guideline, which states that there is insufficient evidence to screen persons at high risk of HCV infection, and recommends against screening adults in the general population. The CDC's and USPSTF's contrasting views previously provoked a lively debate in the editorial pages of American Family Physician, with the USPSTF arguing that screening had not been shown to reduce morbidity or mortality from HCV, and the CDC countering that disease-oriented benefits should eventually translate into positive long-term health outcomes for patients. In fact, the new CDC guideline makes it a point to explain why the two organizations may continue to differ in their recommendations:

The USPSTF prefers data from randomized, controlled trials that begin with randomization into screened and nonscreened groups and follow participants through to morbidity and mortality, yet these data are not available. Although these types of studies provide the most conclusive evidence about the benefits and harms of a screening intervention, they also are resource-intensive and require long periods of follow-up. The CDC based its HCV testing recommendations on the prevalence in the target population, the many persons who are unaware of their infection status, potential benefits of care and treatment, and projections of increasing morbidity and mortality in the absence of an intervention.

According to a recent AFP review article, chronic HCV infection "leads to cirrhosis in about 10 to 20 percent of patients, increasing the risk of complications of chronic liver disease, including portal hypertension, ascites, hemorrhage, and hepatocellular carcinoma." Due to the increased risk of alcohol-induced liver damage in patients with HCV, the CDC also recommends brief screening and intervention for alcohol misuse at the time of HCV diagnosis, a position supported by the USPSTF.