Decrease in HCV Prevalence Could Be Result of Increased Deaths Among Infected

Deaths from chronic hepatitis C virus infection in the United States are grossly underreported, the results of a new study indicate.

While the number of reported cases for people living with hepatitis C virus (HCV) infection in the United States has apparently decreased, researchers are concerned that the decline in prevalence is the result of an increased mortality rate among those infected. The researchers develop this hypothesis in a study published in the March 4, 2014, issue of Annals of Internal Medicine.

Based on their analysis of results compiled by the National Health and Nutrition Examination Survey (NHANES) between 2003 and 2010, which included approximately 30,000 participants older than 20 years of age, the researchers estimate that approximately 2.7 million people in the non-institutionalized US population currently suffer from chronic HCV infection. However, the total number could be much higher in actuality considering the study did not include those who are homeless or incarcerated.

“If HCV infections among high-risk populations not sampled by NHANES are taken into account, our estimated prevalence of chronic infection is conservative,” the authors write.

The study estimates that 1.3% of the general US population (3.6 million) aged 6 years or older has antibodies to HCV (anti-HCV) indicating past or current infection. This represents a decline from estimates of 4.1 million people with anti-HCV based on NHANES data covering 1999 through 2002 and 3.9 million based on data covering 1988 through 1994.

The study finds that HCV infection is most likely to be found in non-Hispanic black men aged 40 to 59 years, with low levels of education and family income. Other factors associated with chronic HCV infection include illicit drug use and having received a blood transfusion prior to 1992.

Worldwide, an estimated 130 million to 170 million people (2% to 3% of the world population) are currently living with HCV, and nearly 500,000 deaths from HCV-related causes are reported annually, primarily from decompensated cirrhosis and liver cancer. Researchers note the importance of identifying those currently undiagnosed with the infection to ascertain the full scope of the HCV epidemic.

“[M]any persons infected with HCV remain untested and unaware of their infection, are unknown to the health care system, are not captured in case-based surveillance because they are typically asymptomatic,” the authors write. “Deaths among persons with HCV infection have superseded deaths in those with HIV infection.”

Although their results indicate a decline in HCV prevalence, the authors caution that this may not be the result of successful treatment. They note that recent analysis suggests HCV is grossly under-recorded on death certificates, implying that the mortality rate among HCV-infected people is much higher than has been reported.

“An increase in mortality among HCV-infected persons could help explain the decrease in prevalence of chronic HCV infection,” the authors write. “Our finding of equivalent decreases in persons who ever had HCV infection (anti-HCV—positive persons) and those who had chronic (current) infection (persons with detectable HCV RNA) supports the suggestion that mortality among chronically infected persons has increased. We would not expect decreases in both if treatment were substantially affecting prevalence, because successful treatment should result in a decrease in the number of persons who are HCV RNA–positive but not in the number of persons who are anti-HCV–positive.”