Hepatitis C virus treatment as prevention in people who inject drugs: testing the evidence.

PURPOSE OF REVIEW: The majority of hepatitis C virus (HCV) infections in the United Kingdom and many developing countries were acquired through injecting. New clinical guidance suggests that HCV treatment should be offered to people with a transmission risk - such as people who inject drugs (PWID) - irrespective of severity of liver disease. We consider the strength of the evidence base and potential problems in evaluating HCV treatment as prevention among PWID. RECENT FINDINGS: There is good theoretical evidence from dynamic models that HCV treatment for PWID could reduce HCV chronic prevalence and incidence among PWID. Economic evaluations from high-income settings have suggested HCV treatment for PWID is cost-effective, and that in many settings HCV treatment of PWID could be more cost-effective than treating those at an equivalent stage with no ongoing transmission risk. Epidemiological studies of older interferon treatments have suggested that PWID can achieve similar treatment outcomes to other patient groups treated for chronic HCV. Impact and cost-effectiveness of HCV treatment is driven by the potential 'prevention benefit' of treating PWID. Model projections suggest that more future infections, end stage liver disease, and HCV-related deaths will be averted than lost through reinfection of PWID treated successfully for HCV. However, there is to date no empirical evidence from trials or observational studies that test the model projections and 'prevention benefit' hypothesis. In part this is because of uncertainty in the evidence base but also there is unlikely to have been a change in HCV prevalence due to HCV treatment because PWID HCV treatment rates historically in most sites have been low, and any scale-up and switch to the new direct acting antiviral has not yet occurred. There are a number of key uncertainties in the data available on PWID that need to be improved and addressed to evaluate treatment as prevention. These include estimates of the prevalence of PWID, measurements of HCV chronic prevalence and incidence among PWID, and how to interpret reinfection rates as potential outcome measures. SUMMARY: Eliminating HCV through scaling up treatment is a theoretical possibility. But empirical data are required to demonstrate that HCV treatment can reduce HCV transmission, which will require an improved evidence base and analytic framework for measuring PWID and HCV prevalence.

Hepatitis C virus testing in adults living with HIV: a need for improved screening efforts.

OBJECTIVES: Guidelines recommend hepatitis C virus (HCV) screening for all people living with HIV (PLWH). Understanding HCV testing practices may improve compliance with guidelines and can help identify areas for future intervention. METHODS: We evaluated HCV screening and unnecessary repeat HCV testing in 8,590 PLWH initiating care at 12 U.S. HIV clinics between 2006 and 2010, with follow-up through 2011. Multivariable logistic regression examined the association between patient factors and the outcomes: HCV screening (≥1 HCV antibody tests during the study period) and unnecessary repeat HCV testing (≥1 HCV antibody tests in patients with a prior positive test result). RESULTS: Overall, 82% of patients were screened for HCV, 18% of those screened were HCV antibody-positive, and 40% of HCV antibody-positive patients had unnecessary repeat HCV testing. The likelihood of being screened for HCV increased as the number of outpatient visits rose (adjusted odds ratio 1.02, 95% confidence interval 1.01-1.03). Compared to men who have sex with men (MSM), patients with injection drug use (IDU) were less likely to be screened for HCV (0.63, 0.52-0.78); while individuals with Medicaid were more likely to be screened than those with private insurance (1.30, 1.04-1.62). Patients with heterosexual (1.78, 1.20-2.65) and IDU (1.58, 1.06-2.34) risk compared to MSM, and those with higher numbers of outpatient (1.03, 1.01-1.04) and inpatient (1.09, 1.01-1.19) visits were at greatest risk of unnecessary HCV testing. CONCLUSIONS: Additional efforts to improve compliance with HCV testing guidelines are needed. Leveraging health information technology may increase HCV screening and reduce unnecessary testing.

Empirical Bayes approach to estimating the number of HIV-infected individuals in hidden and elusive populations.

In this paper we estimate the numbers of intravenous drug users (IVDUs) and commercial sex workers (CSWs) in Thailand infected with human immunodeficiency virus (HIV) who have not developed acquired immunodeficiency syndrome (AIDS) directly from the semi-annual HIV serosurveillance data of Thailand from June 1993 to June 1995. We propose a 'generalized removal model for open populations' for estimating HIV-infected population size within a hidden, elusive, and perhaps high-risk population group, for all sampling time when capture probabilities vary with time. We apply empirical Bayes methodology to the generalized removal model for open populations by using the Gibbs sampler, a Markov chain Monte Carlo method. No assumption on the size of the hidden population in question is needed to implement this procedure. The statistical method proposed here requires very little computing and only a minimum of two sets of serosurvey data to obtain an estimate, thereby providing a simple and viable option in epidemiological studies when either powerful computing facilities or abundant sampling data are lacking.

Nutritional status assessment of HIV-positive drug addicts.

Since human immunodeficiency virus (HIV) is known to lead to modifications of immune function and interrelationships among malnutrition, anergy and drug addiction have been shown, the aim of this work was to assess the nutritional status of 36 male heroin addicts under a period of detoxication (3 months). They were divided into two groups: (1) HIV negative (n = 20) and (2) HIV positive (n = 16); heights, weights and serum albumin concentration were measured and immune function was tested, using delayed hypersensitivity skin tests containing 7 antigens. No significant differences in anthropometric measurements were found between both groups, but anthropometric improvement was shown in every patient after the detoxication period. Serum albumin, often used as a classical index of malnutrition, remained within the normal values in both groups. The whole response to skin tests was depressed in both groups and no significant differences were shown between them. Therefore, these results might suggest that in spite of the apparent anthropometric recovery and the normal values of albumin, a subclinical malnutrition was indicated by the depressed immune function, which was more noticeable in the HIV-positive group.

Blood and plasma donations among a cohort of intravenous drug users.

We evaluated the blood and plasma donation histories of a cohort of 2921 intravenous drug users in Baltimore, Md, and correlated these histories with their human immunodeficiency virus (HIV) serologic status, numbers of CD4 lymphocytes in the peripheral blood, and stigmata of intravenous drug use (scarred veins). Of the 793 intravenous drug users (27.1%) who had donated blood or plasma, 652 (82.2%) donated after they had started using intravenous drugs. Most subjects donated at commercial plasma centers, where they were paid $10 to $15 per donation. Although the HIV-1 seroprevalence of the entire cohort was 24.1%, the HIV-1 seroprevalence among those reporting plasma or blood donations declined progressively with time, from 17.1% in those who last donated in 1985 to 3.6% in those who last donated in 1988-1989. Many of the 437 intravenous drug users who had donated plasma or blood since 1985, when screening for HIV-1 was initiated, had not been notified and counseled about their HIV test results. Current programs to exclude individuals with a history of intravenous drug use from the plasma donor pool should be reevaluated and improved.

KIE: The authors studied the blood and plasma donation histories of a cohort of intravenous drug users who had been recruited for a natural history study of HIV-1 infection. Most subjects who had donated blood after beginning to use intravenous drugs had done so at a commercial plasma center where they had been paid for their donation. According to self-reports, many of the subjects donating since 1985 (when mandatory screening of all donors for HIV antibodies began) had not been notified or counseled about their HIV status by personnel at the centers where they had donated. Nelson, et al. believe that greater efforts are needed to identify and exclude intravenous drug users as blood donors, and to notify and counsel potential donors whose blood tests positive for HIV antibodies.