Current epidemiology of hepatitis E virus infection in the United States: low seroprevalence in the National Health and Nutrition Evaluation Survey.

UNLABELLED: Analysis of the National Health and Nutrition Evaluation Survey (NHANES) 1988-1994 dataset found a relatively high seroprevalence (21%) of hepatitis E virus (HEV) infection in the U.S. general population. Using data obtained within the NHANES 2009-2010 survey, where a high performance assay for HEV was used, we estimated the weighted seroprevalence of HEV infection among U.S. individuals 6 years and older. We also evaluated factors associated with HEV seropositivity. A total of 8,814 individuals were included in the analysis. The median age of study participants was 37 years (interquartile range [IQR] 17-58 years), with 51.2% being female. The weighted national seroprevalence of HEV was 6% (95% confidence interval [CI] 5.1%-6.9%). About 0.5% of those with HEV had evidence of recent exposure (immunoglobulin M-positive). In the univariate analyses, factors associated with HEV seropositivity were increasing age (P-trend<0.001), birth outside of the U.S., Hispanic race, and "meat" consumption (>10 times/month). No significant association was observed with low socioeconomic status, water source, or level of education. In the multivariate analysis, only older age remained predictive of HEV seropositivity. CONCLUSION: The weighted national seroprevalence of HEV in the U.S. is much less than previously reported. Using data obtained with a high performance assay, the seroprevalence of HEV was estimated at 6.0% in the U.S. Based on these results, the seroprevalence of HEV is only one-third as high as previously reported.

The changing epidemiology of hepatitis C virus infection in the United States: National Health and Nutrition Examination Survey 2001 through 2010.

BACKGROUND & AIMS: In light of the 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: 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. RESULTS: The prevalence of anti-HCV in the United Sates decreased from 1.9% (95% CI 1.5%-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.

Persistence and adherence to nucleos(t)ide analogue treatment for chronic hepatitis B.

BACKGROUND & AIMS: Long-term treatment with nucleos(t)ide analogues (NUCs) is associated with increasing rates of antiviral drug resistance. Medication adherence is important in preventing drug resistance. This study aimed to determine, first, the persistence rates and the adherence rates to NUCs in patients with chronic hepatitis B (CHB), and second, the factors associated with adherence. METHODS: Pharmacy claims of three cohorts of patients with CHB who were receiving lamivudine, adefovir, or entecavir in January 2007, January 2008, and January 2009, and data of patients receiving tenofovir in January 2009, were analyzed. Persistence was defined as continuing acquisition of pharmacy claims during a 12-month period and adherence as the percent of days in which patients had medication during the period in which the medication was prescribed. RESULTS: A total of 11,100 patients were included, 4.7% were patients newly started on a NUC and 95.3% were existing patients already on a NUC at the start of each year. The mean ± SD persistence rate was 81 ± 3.8%, and was higher among existing patients than among new patients, 81.4% vs. 73.4% (p < 0.001). The mean ± SD adherence rate was 87.8 ± 19.1% and was higher among existing patients than among new patients, 88% vs. 84.6% (p = 0.001). Multivariate analysis showed that new patients (OR = 0.68, 95% CI 0.53-0.86), those receiving lamivudine (OR = 0.66, 95% CI 0.58-0.76), and young adult patients (OR=0.82, 95% CI 0.74-0.91) were less likely to have adherence rate > 90%. CONCLUSIONS: Persistence and adherence to NUCs were high among CHB patients. Counseling of young and/or new patients on medication adherence may decrease the rate of antiviral drug resistance.