Wednesday, August 29, 2012

Screening for chronic hepatitis C in baby boomers

Earlier this month, 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 were 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. Its 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 is unclear what impact these new 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 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.

Two years ago, I represented the Agency for Healthcare Research and Quality at several of the Department of Health and Human Services' strategy sessions that followed the Institute of Medicine's report calling for increased efforts to reduce the public health burden of chronic hepatitis and liver cancer in the U.S. Chronic hepatitis predominantly affects vulnerable populations, including immigrants from Asia and homeless and incarcerated persons. But I am not sure that the new CDC guideline represents a step in the right direction. On one hand, recently developed drugs for chronic hepatitis C are considerably less toxic than the older ones, and more effective, if effectiveness is measured by disease-oriented outcomes such as viral loads and liver pathology. On the other, a large proportion of persons with hepatitis C will never develop symptoms, but this universal age-cohort screening strategy would expose them all to potentially unnecessary labeling, workup, and treatment, not to mention add hundreds of thousands of patients to health systems for the underserved that are already straining to meet demand for subspecialist services. It's a tough call to make, and I will be watching the USPSTF closely to see how they weigh the benefits and harms.


Some content from the above post was first published on the AFP Community Blog.