Previous Exposure to HCV Among Persons Born During 1945–1965

Abstract and Introduction

Abstract

Objectives. We examined HCV exposure prevalence and predictors among persons in the United States born during 1945–1965.

Methods. With data from the 1999–2008 National Health and Nutrition Examination Survey, we calculated the proportion of persons born during 1945–1965 who tested positive for HCV antibody (anti-HCV) and analyzed the prevalence by sociodemographic and behavioral risk factors.

Results. Anti-HCV prevalence in the 1945–1965 birth cohort was 3.2% (95% confidence interval [CI] = 2.8%, 3.8%), substantially higher than among other adults (0.9%). Within the cohort, anti-HCV prevalence was higher among non-Hispanic Blacks (6.4%; 95% CI = 5.3%, 7.7%), persons with injection drug use histories (56.8%; 95% CI = 48.4%, 64.8%), and persons with elevated alanine aminotransferase levels (12.7%; 95% CI = 10.7%, 15.1%). Injection drug use (adjusted odds ratio = 98.4; 95% CI = 58.8, 164.5) was the strongest anti-HCV prevalence predictor. Among anti-HCV–positive persons, 57.8% reported having 2 or more alcoholic drinks daily.

Conclusions. With the high prevalence of HCV among persons born during 1945–1965, the increasing morbidity and mortality associated with HCV, and reductions in liver cancer and HCV-related mortality when HCV is eradicated, it is critically important to identify persons with HCV and link them to appropriate care.

Introduction

In the United States, the incidence of HCV infection rose dramatically through the 1970s and 1980s reaching more than 200 000 new infections per year through the mid- to late-1980s.^[1] This high incidence resulted in a disproportionately high burden of HCV infection among Americans who were born between the mid-1940s and the mid-1960s, a birth cohort popularly referred to as the baby boom generation.^[2] Alter et al. first documented the relatively high prevalence of HCV infection among this cohort in their analysis of1988–1994 National Health and Nutrition Examination Survey (NHANES) data, reporting that 65% of persons with HCV infection were aged 30 to 49 years during the survey period.^[3] In an analysis of NHANES data from 1999 to 2002, a similarly high proportion of all persons with HCV antibody had been born from 1945 through 1964.^[1] This cohort effect on the high prevalence of HCV infection in the baby boom generation has been attributed largely to exposures (principally injection drug use [IDU] and blood transfusion before 1992) that occurred many years before the survey periods.^[1,3] However, a significant proportion of HCV-infected persons do not report any risk factors,^[4–6] perhaps because of fear of being stigmatized,^[7] or simply lack of recall or knowledge of exposures such as those that may occur in health care settings.^[8,9]

A validated Markov model forecasting lifetime morbidity and mortality attributable to HCV infection projected that of 2.9 million persons with untreated HCV infection who did not have cirrhosis of the liver in 2005, 1 071 000 (36.8%) will die from complications of HCV.^[10] In the United States, HCV-associated disease is the leading indication for liver transplantation and HCV infection is a leading cause of hepatocellular carcinoma.^[11–14] Approximately 73.9% of HCV-associated mortality occurs among persons born from1945 to 1965.^[15]

In 1998, the Centers for Disease Control and Prevention recommended^[16] that persons with certain risk factors (e.g., any history of IDU) or medical conditions (e.g., persistently elevated alanine aminotransferase [ALT] levels) be tested for HCV infection. Despite these recommendations, testing practices over the past decade have had limited success in identification of HCV infection in the United States as estimates of the proportion of persons who are unaware of their infection range from 40% to 85%.^[17–20] Contributing to the limited success of the recommendations is the difficulty in obtaining risk behavior history that occurred in the distant past, the primarily asymptomatic nature of the infection, and a less than optimal level of physician knowledge regarding the natural history and prevalence of infection, the current recommendations for testing, and interpretation of test results.^[21–24]

In 2011, the prospects for successful medical treatment of HCV infection were significantly improved with the US Food and Drug Administration licensure of 2 direct-acting antiviral medications, both in the protease inhibitor class. In clinical trials, the rates of sustained viral response—equivalent to a "virological cure"—increased from 44% with use of the current standard regimen, to 75% when a direct-acting antiviral medication was added to that regimen in treatment of persons infected with HCV genotype 1, the genotype that is most common in the United States.^[25] Since this article was accepted for publication, the US Food and Drug Administration has approved new HCV medications^[26,27] that have further increased cure rates to as high as 90% in clinical trials.

Persons who achieve a sustained viral response after treatment experience significantly less liver-related morbidity (including hepatocellular carcinoma),^[28] less liver-related mortality,^[29] and reductions in all-cause mortality.^[30] However, the potential population benefits from these improvements in treatment effectiveness will be limited unless there are concurrent increases in the rate of identification and treatment of HCV-infected persons.^[31]

Because of the limited effectiveness of riskbased testing strategies to date and the high prevalence of HCV infection and projected disease burden, the Centers for Disease Control and Prevention recently issued the Recommendations for the Identification and Initial Care of Chronic Hepatitis C Virus Infection Among Persons Born During 1945–1965^[32] with the goal of identifying persons with HCV infection who are undiagnosed. The recommendation was subsequently made by the US Preventive Services Task Force.^[33] The purpose of the current study was to determine the proportion of persons in the birth cohort who were positive for antibody to HCV (anti-HCV), and to examine the sociodemographic and behavioral risk factors associated with anti-HCV prevalence.

Am J Public Health. 2014;104(3):474-481. © 2014 American Public Health Association