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New NHANES: The Changing Epidemiology of Hepatitis C Virus Infection in the United States: National Health and Nutrition Examination Survey 2001 through 2010
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"Conclusions: We describe the current epidemiology of hepatitis C in the non-institutionalized civilian US population as of 2010. About 2.2 million persons are chronically infected with Hepatitis C in the US. Most of those infected are prevalent (born between 1945 and 1965), rather than incident cases. The prevalence of hepatitis C infection, which was on the decline in the US, has stabilized since 2006. With an anticipated increase in HCV-related complications as the 1945-1965 birth cohort ages, there is an increased need to identify and treat infected persons, especially in light of the advent of more effective and tolerable HCV therapies. The results of this NHANES survey suggest that screening for HCV should also be considered in persons migrating into the US. Future studies should explore reasons for no further decline in HCV prevalence since 2006."
"There are several important findings in this analysis of the NHANES survey. The primary observation of this study is that the prevalence of antibodies to HCV in the noninstitutionalized United States population is 1.3% and has not declined since 2006.[27,28] This corresponds to an estimated 3.5 million people in the United States who are 6 years and older. This prevalence is almost certainly an underestimate as NHANES does not include some high risk populations, including the incarcerated, hemodialysis patients and the homeless. Of all persons with anti-HCV, 2.3 million had evidence of chronic infection as suggested by a positive HCV-RNA. Because HCV-RNA testing is performed only on a single sample, it is possible that some cases with chronic infection are being missed given that viremia can be transient.[29]"
"Injection drug use remains the strongest risk factor for HCV infection.[47-49] .......The prevalence was noted to be highest among male non-Hispanic Blacks (2.2%) compared to Non-Hispanic whites (1.3%) [2.9% among Black men, 1.7% among Black women]......sexual transmission of HCV is well documented among HIV infected men who have sex with men.....Abnormal ALT was very strongly associated with anti-HCV presence. However, [a person may have normal ALT but still have HCV] the positive predictive value of ALT as a screening tool for HCV remains very low even among the 1945-1965 birth cohort. Unfortunately, abnormal ALT remains the main indication for HCV screening in community practices.[57] Studies from other settings have also found elevated ALT not to be predictive of HCV infection.[58-60]"
Greater than two-thirds (70.1%) of all seroprevalent cases were in the 45-65 years old age group (1945-1965 birth cohort). The Centers for Disease Control and US Preventive Services Task Force recommend HCV screening in people born between 1945 and 1965, which corresponds to persons aged 48 to 68 years in 2013.[36,37] From 2001-2010, we were able to show a birth cohort effect with respect to prevalent infection. Figure 3 clearly shows that the 1945-1965 birth cohort accounts for most of the prevalent cases at each time point. It is anticipated that, as this cohort ages, we will see more HCV related complications such as liver cirrhosis and hepatocellular cancer secondary to HCV acquired several decades ago.[38,39] Furthermore, in light of dramatically changing hepatitis C therapeutic landscape with highly effective and well tolerated pangenomic HCV treatment regimens[40-42], timely diagnosis becomes even more important. Early identification of infected individuals could curb HCV-related morbidity and mortality."
"Results from NHANES data are only applicable to the noninstitutionalized civilian population in the US, which represents only a portion of all HCV infected persons. These results cannot be extrapolated to some high risk groups such as the homeless or incarcerated, for whom the prevalence is likely to be higher than that of the general population. Our study relied on self-reporting and thus subject to recall bias. The use of IDUs is a socially stigmatized illegal activity that can result in people being unwilling to admit to this behavior. The latter may have resulted in an underestimation of these factors."
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Article in Press
The Changing Epidemiology of Hepatitis C Virus Infection in the United States: National Health and Nutrition Examination Survey 2001 through 2010
Abstract
Background
In light of dramatically changing hepatitis C therapeutic landscape, knowledge of the current burden of HCV infection in the general population of the United States is critical.
Methods and Participants
The National Health and Nutrition Examination survey collects nationally representative data on HCV infection in the civilian population of the United States. Data from 2001 to 2010 were combined for this study. HCV testing was completed in 38,025 participants.
It collates nationally representative data on the health and nutritional status of the non-institutionalized, civilian population of the United States
Results
The prevalence of anti-HCV in the United Sates decreased from 1.9% (95% CI1.5%-2.5%) in 2001-2002 to 1.3% (95% CI 0.9%-1.8%) in 2005-2006, and remained stable up to 2010. About 67% of all infected persons were positive for HCV RNA, indicating 2.3 million people with chronic HCV infection, of whom 68% have genotype 1. Seventy percent of infected persons were born between 1945 and 1965, with prevalence of 3.5% (95% CI 2.2%-4.8%). The stable rate since 2006 is mostly related to prevalent cases and foreign born persons migrating into US. Other important risk factors include less education and low economic status. Race, HIV status, number of sexual partners and blood transfusions are no longer associated with HCV infection.
Conclusions
As of 2010, approximately 2.3 million persons were chronically infected with Hepatitis C in the US. Most of those infected are prevalent, rather than incident cases. The prevalence of HCV was on the decline, but has stabilized since 2006. Future studies should explore reasons for no decline in HCV prevalence since 2006.
"The prevalence was noted to be highest among male non-Hispanic Blacks (2.2%) compared to Non-Hispanic whites (1.3%)."
"Overall, there was a trend toward increase in the prevalence of anti-HCV among persons born outside of the USA. The prevalence increased from 0.3% to 0.8% between 2001 and 2006. However, it decreased to 0.4% in 2007 but as of 2010, it was up to 1.0%"."
"The strongest risk factors for having anti-HCV included people aged 45 to 65 years old, being born in the United States, less than high school education, lifetime drug use, abnormal alanine aminotransferase levels(ALT>39U/L) and having antibodies to herpes simplex virus type 2. The positive predictive value for ALT for persons less than 70 years old and for the 1945-1965 birth cohort were 5.14% and 6.7% respectively. Race, HIV status, service in US military and gender were not predictive after adjustment."
"Over the last decade, IVDU has decreased significantly in the USA.[32,33]"
"Injection drug use remains the strongest risk factor for HCV infection.[47-49] The CDC estimates that most new cases of HCV infection occur in IDU individuals and this group is partially responsible for the non decline in HCV prevalence since 2006. Annual HCV incidence rates ranging from 8 to 25% have been reported in young adult injectors.[50] The highest incidence rates occur early after initiation of injection drug use[51-53], and prevention strategies targeting new injectors or persons at risk of starting should help avert this trend.[54] Early identification of this high risk population provides unique opportunity for interventions aimed at breaking the chain of transmission as well articulated by Page et al."
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