Approximately 1% of US Residents Have Chronic HCV Infection

Laurie Barclay, MD

March 03, 2014

About 2.7 million US residents had chronic hepatitis C virus (HCV) infection in 2003-2010, which is about 500,000 fewer than a similar estimate for 1999-2002, according to findings of a nationally representative household survey published in the March 3 issue of the Annals of Internal Medicine.

"The Institute of Medicine recently concluded that it is essential to know the dimensions and direction of this epidemic, which has major implications for health burden and costs for the United States," write Maxine M. Denniston, MSPH, from the National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, and colleagues. "Current treatment can cure HCV in a substantial proportion of persons who complete therapy, thereby decreasing the risk for hepatocellular carcinoma and all-cause mortality. However, many persons infected with HCV remain untested and unaware of their infection, are unknown to the health care system, and are not captured in case-based surveillance because they are typically asymptomatic."

The authors also note that mortality from HCV exceeds that of HIV infection in the United States.

The study sample consisted of 30,074 US noninstitutionalized civilian residents who participated in the National Health and Nutrition Examination Survey (NHANES) between 2003 and 2010. To determine demographic characteristics and possible risks and exposures for HCV infection, participants were interviewed, and those who were at least 6 years of age gave serum samples for HCV antibody testing. Samples with positive or indeterminate results were tested for HCV RNA to determine current chronic infection.

Findings Suggest Increased Mortality From HCV Infection

Estimated prevalence of HCV infection in the US noninstitutionalized civilian population was 1.0% (95% confidence interval [CI], 0.8% - 1.2%), based on 273 participants with positive HCV RNA testing. This translates to 2.7 million chronically infected persons (95% CI, 2.2 - 3.2 million), or a decrease of about half a million since the previous survey. The investigators suggested that this decrease could be attributed to increased mortality from HCV infection and its complications.

Persons with chronic HCV infection were more likely to be 40 to 59 years old, male, non-Hispanic black, and less educated and to have a lower family income.

Illicit drug use, including injected drugs, and having a blood transfusion before 1992 were significantly associated with chronic HCV infection. However, nearly half (49%) of persons with chronic HCV infection did not report having either risk factor, suggesting that risk-based screening may not be the best way to identify chronically infected persons. The Centers for Disease Control and Prevention currently recommend a 1-time HCV screening for all persons born between 1945 and 1965.

"This analysis estimated that approximately 2.7 million U.S. residents in the population sampled by NHANES have chronic HCV infection, about 500 000 fewer than estimated in a similar analysis between 1999 and 2002," the study authors write. "These data underscore the urgency of identifying the millions of persons who remain infected and linking them to appropriate care and treatment."

Limitations of this study include the failure to survey incarcerated and homeless persons, which could limit generalizability, and an inability to provide statistically valid estimates by age or by sex and age within race/ethnicity.

"If HCV infections among high-risk populations not sampled by NHANES are taken into account, our estimated prevalence of chronic infection is conservative," the study authors conclude. "An important public health implication is that our analysis suggests decreases in prevalence that probably reflect increasing mortality from HCV-related conditions."

The authors have disclosed no relevant financial relationships.

Ann Intern Med. 2014;160:293-300.


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