Regional and global summary estimates of antibody to hepatitis C virus prevalence in detainee populations: Seeing the forest and the trees?

H epatitis C virus (HCV) infection is the most common blood-borne infection in the United States and worldwide. Using systematic review and mathematical modeling, Hanifiah et al. recently estimated that the global prevalence of antibody to HCV (anti-HCV) increased from 2.3% (95% uncertainty interval [UI]: 2.1%-2.5%) to 2.8% (95% UI: 2.6%-3.1%) from 1990 to 2005, for an increase in the number of anti-HCV-positive persons from 122 to 184 million. Although this estimate is higher than some previously published studies, the researchers rightly suggest that their estimate may nonetheless be “conservative” or may underestimate the global prevalence of anti-HCV. Their systematic review specifically excluded studies of high-risk populations (e.g., injection drug users, paid blood donors, homeless persons, and detained or incarcerated persons), and their review included national population-based studies (e.g., U.S. National Health and Nutrition Examination Survey; NHANES), which systematically excluded institutionalized persons, including those detained in jails or prisons, who are at increased HCV risk. The exclusion of penal detainees from national, regional, and global estimates of anti-HCV prevalence is particularly problematic. The International Center for Prison Studies estimated that, as of May 2011, more than 10.1 million people were held in penal institutions worldwide as pretrial detainees/remand prisoners or sentenced prisoners (hereafter, inclusively termed “detainees”). Throughout the world, studies of detainee populations have consistently shown elevated prevalence of anti-HCV, compared to noninstitutionalized, local reference populations. In the United States, for example, anti-HCV prevalence in detainee populations has historically been estimated to be 15-20 times greater than nonincarcerated populations. Based on 1999-2002 NHANES data, the estimated anti-HCV prevalence was 1.6% (range, 1.3%-1.9%) among noninstitutionalized persons in the United States. In 12 selected studies of anti-HCV prevalence in U.S. detainee populations conducted from 1985 to 2002, anti-HCV prevalence estimates ranged from 23.1% to 41%. Notably, from these same studies, anti-HCV prevalence estimates among U.S. detainees with a history of injection drug use were exceptionally high, ranging from 32.3% to 82.8%. Given the large estimated number of detained persons worldwide and the consistently high estimated prevalence among detainees in many countries where data are available, estimates of the anti-HCV burden that exclude detainees are likely underestimates. National, regional, and global estimates of anti-HCV prevalence in detainee populations are needed to produce better, “truer” estimates of the burden of HCV infection. In this issue of HEPATOLOGY, Larney et al. provide regional and global estimates of anti-HCV prevalence among detainees in “prisons and other closed settings”. Prisons and other closed settings was defined as prisons, jails, juvenile detention facilities, pretrial detention centers, and extrajudicial detention centers for people who use drugs and excluded psychiatric institutions and immigration detention facilities. Estimates were based upon systematic review and meta-analysis of 93 studies reported between 1990 and September 2012. Specifically, regional summary prevalence estimates were produced using meta-analytic techniques, and, in turn, regional summary prevalence estimates were summarized using meta-analysis to produce a global summary prevalence estimate. To produce regional and global estimated counts of anti-HCV-positive prisoners, regional summary prevalence estimates were applied to the number of prisoners reported or estimated in the region. Regional summary estimates were based on varying numbers of studies (from 1 in Central Asia to Abbreviations: anti-HCV, antibody to HCV; CI, confidence interval; HCV, hepatitis C virus; NHANES, National Health and Nutrition Examination Survey; UI, uncertainty interval. Address reprint requests to: Amy J. Harzke, M.Div., M.P.H., Dr.P.H., Correctional Managed Care, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0449. E-mail: ajharzke@utmb.edu; fax: 409-747-6270. Copyright VC 2013 by the American Association for the Study of Liver Diseases. View this article online at wileyonlinelibrary.com. DOI 10.1002/hep.26474 Potential conflict of interest: Nothing to report.