Strategies for the treatment of Hepatitis C in an era of interferon-free therapies: what public health outcomes do we value most?

Population-level estimates of hepatitis C reinfection post scale-up of direct-acting antivirals among people who inject drugs

BACKGROUND & AIMS

Scale-up of highly effective direct-acting antivirals (DAAs) for HCV among people who inject drugs (PWID) in Scotland has led to a reduction in the prevalence of viraemia in this population. However, the extent of reinfection among those treated with DAAs remains uncertain. We estimated HCV reinfection rates among PWID in Scotland by treatment setting, pre- and post-introduction of DAAs, and the potential number of undiagnosed reinfections resulting from incomplete follow-up testing.

METHODS

Through linkage of national clinical and laboratory HCV data, a retrospective cohort of PWID who commenced treatment between 2000-2018 and achieved a sustained virological response (SVR) were followed up for reinfection to December 2019. Reinfection was defined as a positive HCV antigen or RNA test.

RESULTS

Of 5,686 SVRs among 5,592 PWID, 4,126 (73%) had an HCV RNA or antigen test post-SVR. Of those retested, we identified 361 reinfections (3.9/100 person-years [PY]). The reinfection rate increased from 1.5/100 PY among PWID treated in 2000-2009 to 8.8/100 PY in 2017-2018. The highest reinfection rates were observed among those treated in prison (14.3/100 PY) and community settings (9.5/100 PY). Among those treated in the DAA era (2015-2018), 68% were tested within the first year post-SVR but only 30% in the second year; while 169 reinfections were diagnosed in follow-up, an estimated 200 reinfections (54% of the estimated total) had gone undetected.

CONCLUSIONS

HCV reinfection rates among PWID in Scotland have risen alongside the scale-up of DAAs and broadened access to treatment for those at highest risk, through delivery in community drug services. Promotion of HCV testing post-SVR among PWID is essential to ensure those reinfected are identified and retreated promptly.

LAY SUMMARY

Increased rates of hepatitis C reinfection in Scotland were observed following the rapid scale-up of highly effective direct-acting antiviral (DAA) treatments among people who inject drugs. This demonstrates that community-based treatment pathways are reaching high-risk groups, regarded vital in efforts to eliminate the virus. However, we estimate that less than half of reinfections have been detected in the DAA era because of inadequate levels of retesting beyond the first year following successful treatment. Sustained efforts that involve high coverage of harm reduction measures and high uptake of annual testing are required to ensure prompt diagnosis and treatment of those reinfected if the goals of elimination are to be met.

Declining incidence of hepatitis C related hepatocellular carcinoma in the era of interferon-free therapies: A population-based cohort study

BACKGROUND & AIMS

The impact of interferon (IFN)-free therapies on the epidemiology of hepatitis C virus (HCV) related hepatocellular carcinoma (HCC) is not well understood at a population level. Our goal was to bridge this evidence gap.

METHODS

This study included all patients in Scotland with chronic HCV and a diagnosis of cirrhosis during 1999-2019. Incident cases of HCC, episodes of curative HCC therapy, and HCC-related deaths were identified through linkage to nationwide registries. Three time periods were examined: 1999-2010 (pegylated interferon-ribavirin [PIR]); 2011-2013 (First-generation DAA); and 2014-2019 (IFN-free era). We used regression modelling to determine time trends for (i) number diagnosed and living with HCV cirrhosis, (ii) HCC cumulative incidence, (iii) HCC curative treatment uptake and (iv) post-HCC mortality.

RESULTS

3347 cirrhosis patients were identified of which 381 (11.4%) developed HCC. After HCC diagnosis, 140 (36.7%) received curative HCC treatment and there were 202 deaths from HCC. The average annual number of patients diagnosed and living with HCV cirrhosis was approximately seven times higher in the IFN-free versus the PIR era, whereas the number of incident HCCs was four times higher. However, the cumulative incidence of HCC was significantly lower in the IFN-free versus PIR era (sdHR: 0.65; 95%CI:0.47-0.88; P = .006). Among HCC patients, diagnosis in the IFN-free era was not associated with improved uptake of curative treatment (aOR:1.18; 95%CI:0.69-2.01; P = .54), or reduced post-HCC mortality (sdHR: 0.74; 95%CI:0.53-1.05; P = .09).

CONCLUSIONS

The cumulative incidence of HCC is declining in HCV cirrhosis patients, but uptake of curative HCC therapy and post-HCC survival remains suboptimal.

The impact of direct-acting antivirals on hepatitis C viraemia among people who inject drugs in England; real-world data 2011-2018

Direct-acting antiviral (DAA) therapy for anybody with viraemic HCV infection has been scaled-up in England since 2017. To assess early impacts, we investigated trends in, and factors associated with, HCV viraemia among people who inject drugs (PWID). We also examined trends in self-reported treatment access. Bio-behavioural data from an annual, national surveillance survey of PWID (2011-2018) estimated trends in viraemic prevalence among HCV antibody-positive PWID. Multivariable logistic regression identified characteristics independently associated with viraemia. Trends in treatment access were examined for PWID with known infection. Between 2011 and 2016, viraemic prevalence among antibody-positive PWID remained stable (2011, 57.7%; 2016, 55.8%) but decreased in 2017 (49.4%) and 2018 (50.4%) (both p < 0.001). After adjustment for demographic and behavioural characteristics, there remained significant reduction in viraemia in 2017 (adjusted odds ratio [aOR] 0.79, 95% CI 0.65-0.94) and 2018 (aOR 0.79, 95% CI 0.66-0.93) compared to 2016. Other factors associated with viraemia were male gender (aOR 1.68, 95% CI 1.53-1.86), geographical region, injecting in past year (aOR 1.26, 95% CI 1.13-1.41), imprisonment (aOR 1.14, 95% CI 1.04-1.31) and homelessness (aOR 1.17, 95% CI 1.04-1.31). Among non-viraemic PWID with known infection, the proportion reporting ever receiving treatment increased in 2017 (28.7%, p < 0.001) and 2018 (38.9%, p < 0.001) compared to 2016 (14.5%). In conclusion, there has been a small reduction in HCV viraemia among antibody-positive PWID in England since 2016, alongside DAA scale-up, and some indication that treatment access has improved in the same period. Population-level monitoring and focus on harm reduction is critical for achieving and evaluating elimination.

Reduction in the population prevalence of hepatitis C virus viraemia among people who inject drugs associated with scale-up of direct-acting anti-viral therapy in community drug services: real-world data

BACKGROUND AND AIMS

There has been little empirical evidence to show the 'real-world' impact of scaling-up direct-acting anti-viral (DAA) treatment among people who inject drugs (PWID) on hepatitis C virus (HCV) viraemia at a population level. We aimed to assess the population impact of rapid DAA scale-up to PWID delivered through community services-including drug treatment, pharmacies, needle exchanges and prisons-in the Tayside region of Scotland, compared with Greater Glasgow and Clyde (GGC) and the Rest of Scotland (RoS).

DESIGN, SETTING AND PARTICIPANTS

Natural experiment, evaluated using data from national biennial surveys of PWID and national clinical data. Services providing injecting equipment (2010-18) and HCV treatment clinics (2017-18) across Scotland. A total of 12 492 PWID who completed a questionnaire and provided a blood spot (tested for HCV-antibodies and RNA); 4105 individuals who initiated HCV treatment.

INTERVENTION AND COMPARATOR, MEASUREMENTS

The intervention was rapid DAA scale-up among PWID, which occurred in Tayside. The comparator was GGC/RoS. Trends in HCV viraemia and uptake of HCV therapy over time; sustained viral response (SVR) rates to therapy by region and treatment setting.

FINDINGS

Uptake of HCV therapy (last year) among PWID between 2013-14 and 2017-18 increased from 15 to 43% in Tayside, 6 to 16% in GGC and 11 to 23% in RoS. Between 2010 and 2017-18, the prevalence of HCV viraemia (among antibody-positives) declined from 73 to 44% in Tayside, 67 to 58% in GGC and 64 to 55% in RoS. The decline in viraemia was greater in Tayside [2017-18 adjusted odds ratio (aOR) = 0.47, 95% confidence interval (CI) = 0.30-0.75, P = 0.001] than elsewhere in Scotland (2017-18 aOR = 0.89, 95% CI = 0.74-1.07, P = 0.220) relative to the baseline of 2013-14 in RoS (including GGC). Per-protocol SVR rates among PWID treated in community sites did not differ from those treated in hospital sites in Tayside (97.4 versus 100.0%, P = 0.099).

CONCLUSIONS

Scale-up of direct-acting anti-viral treatment among people who inject drugs can be achieved through hepatitis C virus (HCV) testing and treatment in community drug services while maintaining high sustained viral response rates and, in the Tayside region of Scotland, has led to a substantial reduction in chronic HCV in the population.

Excitable models: Projections, targets, and the making of futures without disease

In efforts to control disease, mathematical models and numerical targets play a key role. We take the elimination of a viral infection as a case for exploring mathematical models as 'evidence-making interventions'. Using interviews with mathematical modellers and implementation scientists, and focusing on the emergence of models of 'treatment-as-prevention' in hepatitis C control, we trace how projections detach from their calculative origins as social and policy practices. Drawing on the work of Michel Callon and others, we show that modelled projections of viral elimination circulate as 'qualculations', taking flight via their affects, including as anticipation. Modelled numerical targets do not need 'actual numbers' or precise measurements to perform their authority as evidence of viral elimination or as situated matters-of-concern. Modellers grapple with the ways that their models transform in policy and social practices, apparently beyond reasonable calculus. We highlight how practices of 'holding-on' to projections in relation to imaginaries of 'evidence-based' science entangle with the 'letting-go' of models beyond calculus. We conclude that the 'virtual precision' of models affords them fluid evidence-making potential. We imagine a different mode of modelling science in health, one more attuned to treating projections as qualculative, affective and relational, as excitable matter.

Population impact of direct-acting antiviral treatment on new presentations of hepatitis C-related decompensated cirrhosis: a national record-linkage study

OBJECTIVE

Population-based studies demonstrating the clinical impact of interferon-free direct-acting antiviral (DAA) therapies are lacking. We examined the impact of the introduction of DAAs on HCV-related decompensated cirrhosis (DC) through analysis of population-based data from Scotland.

DESIGN

Through analysis of national surveillance data (involving linkage of HCV diagnosis and clinical databases to hospital and deaths registers), we determined i) the scale-up in the number of patients treated and achieving a sustained viral response (SVR), and ii) the change in the trend of new presentations with HCV-related DC, with the introduction of DAAs.

RESULTS

Approximately 11 000 patients had been treated in Scotland over the 8-year period 2010/11 to 2017/18. The scale-up in the number of patients achieving SVR between the pre-DAA and DAA eras was 2.3-fold overall and 5.9-fold among those with compensated cirrhosis (the group at immediate risk of developing DC). In the pre-DAA era, the annual number of HCV-related DC presentations increased 4.6-fold between 2000 (30) and 2014 (142). In the DAA era, presentations decreased by 51% to 69 in 2018 (and by 67% among those with chronic infection at presentation), representing a significant change in trend (rate ratio 0.88, 95% CI 0.85 to 0.90). With the introduction of DAAs, an estimated 330 DC cases had been averted during 2015-18.

CONCLUSIONS

National scale-up in interferon-free DAA treatment is associated with the rapid downturn in presentations of HCV-related DC at the population-level. Major progress in averting HCV-related DC in the short-term is feasible, and thus other countries should strive to achieve the same.

How to think with models and targets: Hepatitis C elimination as a numbering performance

The field of public health is replete with mathematical models and numerical targets. In the case of disease eliminations, modelled projections and targets play a key role in evidencing elimination futures and in shaping actions in relation to these. Drawing on ideas within science and technology studies, we take hepatitis C elimination as a case for reflecting on how to think with mathematical models and numerical targets as 'performative actors' in evidence-making. We focus specifically on the emergence of 'treatment-as-prevention' as a means to trace the social and material effects that models and targets make, including beyond science. We also focus on how enumerations are made locally in their methods and events of production. We trace the work that models and targets do in relation to three analytical themes: governing; affecting; and enacting. This allows us to situate models and targets as technologies of governance in the constitution of health, which affect and are affected by their material relations, including in relation to matters-of-concern which extend beyond calculus. By emphasising models and targets as enactments, we draw attention to how these devices give life to new enumerated entities, which detach from their calculative origins and take flight in new ways. We make this analysis for two reasons: first, as a call to bring the social and enumeration sciences closer together to speculate on how we might think with models and targets differently and more carefully; and second, to encourage an approach to science which treats evidencing-making interventions, such as models and targets, as performative and political.

Real-world impact following initiation of interferon-free hepatitis C regimens on liver-related outcomes and all-cause mortality among patients with compensated cirrhosis

Few studies have investigated clinical outcomes among patients with cirrhosis who were treated with interferon (IFN)-free direct-acting antiviral (DAA). We aimed to quantify treatment impact on first decompensated cirrhosis hospital admission, first hepatocellular carcinoma (HCC) admission, liver-related mortality and all-cause mortality among a national cohort of cirrhotic patients. Through record linkage between Scotland's HCV Clinical Database and inpatient/day-case hospitalization and deaths records, a study population comprising chronic HCV-infected patients with compensated cirrhosis and initiated on IFN-free DAA between 1 March 2013 and 31 March 2018 was analysed. Cox regression evaluated the association of each clinical outcome with time-dependent treatment status (on treatment, responder, nonresponder or noncompliant), adjusting for patient factors including Child-Pugh class. Among the study population (n = 1073) involving 1809 years of follow-up, 75 (7.0%) died (39 from liver-related causes), 47 progressed to decompensated cirrhosis, and 28 developed HCC. Compared with nonresponders, treatment response (96% among those attending their 12 weeks post-treatment SVR test) was associated with a reduced relative risk of decompensated cirrhosis (hazard ratio [HR] = 0.14; 95% CI: 0.05-0.39), HCC (HR = 0.17; 95% CI: 0.04-0.79), liver-related death (HR = 0.13; 95% CI: 0.05-0.34) and all-cause mortality (HR = 0.30; 95% CI: 0.12-0.76). Compared with responders, noncompliant patients had an increased risk of liver-related (HR = 6.73; 95% CI: 2.99-15.1) and all-cause (HR = 5.45; 95% CI: 3.07-9.68) mortality. For HCV patients with cirrhosis, a treatment response was associated with a lower risk of severe liver complications and improved survival. Our findings suggest additional effort is warranted to address the higher mortality among the minority of cirrhotic patients who do not comply with DAA treatment or associated RNA testing.

Securing sustainable funding for viral hepatitis elimination plans

The majority of people infected with chronic hepatitis C virus (HCV) in the European Union (EU) remain undiagnosed and untreated. During recent years, immigration to EU has further increased HCV prevalence. It has been estimated that, out of the 4.2 million adults affected by HCV infection in the 31 EU/ European Economic Area (EEA) countries, as many as 580 000 are migrants. Additionally, HCV is highly prevalent and under addressed in Eastern Europe. In 2013, the introduction of highly effective treatments for HCV with direct-acting antivirals created an unprecedented opportunity to cure almost all patients, reduce HCV transmission and eliminate the disease. However, in many settings, HCV elimination poses a serious challenge for countries' health spending. On 6 June 2018, the Hepatitis B and C Public Policy Association held the 2nd EU HCV Policy summit. It was emphasized that key stakeholders should work collaboratively since only a few countries in the EU are on track to achieve HCV elimination by 2030. In particular, more effort is needed for universal screening. The micro-elimination approach in specific populations is less complex and less costly than country-wide elimination programmes and is an important first step in many settings. Preliminary data suggest that implementation of the World Health Organization (WHO) Global Health Sector Strategy on Viral Hepatitis can be cost saving. However, innovative financing mechanisms are needed to raise funds upfront for scaling up screening, treatment and harm reduction interventions that can lead to HCV elimination by 2030, the stated goal of the WHO.

Prioritising Hepatitis C treatment in people with multiple injecting partners maximises prevention: A real-world network study

OBJECTIVE

To describe an injecting network of PWID living in an isolated community on the Isle of Wight (UK) and the results of a agent-based simulation, testing the effect of Hepatitis C (HCV) treatment on transmission.

METHOD

People who inject drugs (PWID) were identified via respondent driven sampling and recruited to a network and bio-behavioural survey. The injecting network they described formed the baseline population and potential transmission pathways in an agent-based simulation of HCV transmission and the effects of treatment over 12 months.

RESULTS

On average each PWID had 2.6 injecting partners (range 0-14) and 137 were connected into a single component. HCV in the network was associated with a higher proportion of positive injecting partners (p = 0.003) and increasing age (p = 0.011). The treatment of well-connected PWID led to significantly fewer new infections of HCV than treating at random (10 vs. 7, p<0.001). In all scenarios less than one individual was re-infected.

CONCLUSION

In our model the preferential treatment of well-connected PWID maximised treatment as prevention. In the real-world setting, targeting treatment to actively injecting PWID, with multiple injecting partners may therefore represent the most efficient elimination strategy for HCV.

Mathematical modeling of hepatitis c virus (HCV) prevention among people who inject drugs: A review of the literature and insights for elimination strategies

In 2016, the World Health Organization issued global elimination targets for hepatitis C virus (HCV), including an 80% reduction in HCV incidence by 2030. The vast majority of new HCV infections occur among people who inject drugs (PWID), and as such elimination strategies require particular focus on this population. As governments urgently require guidance on how to achieve elimination among PWID, mathematical modeling can provide critical information on the level and targeting of intervention are required. In this paper we review the epidemic modeling literature on HCV transmission and prevention among PWID, highlight main differences in mathematical formulation, and discuss key insights provided by these models in terms of achieving WHO elimination targets among PWID. Overall, the vast majority of modeling studies utilized a deterministic compartmental susceptible-infected-susceptible structure, with select studies utilizing individual-based network transmission models. In general, these studies found that harm reduction alone is unlikely to achieve elimination targets among PWID. However, modeling indicates elimination is achievable in a wide variety of epidemic settings with harm reduction scale-up combined with modest levels of HCV treatment for PWID. Unfortunately, current levels of testing and treatment are generally insufficient to achieve elimination in most settings, and require further scale-up. Additionally, network-based treatment strategies as well as prison-based treatment and harm reduction provision could provide important additional population benefits. Overall, epidemic modeling has and continues to play a critical role in informing HCV elimination strategies worldwide.

Innovative strategies for the elimination of viral hepatitis at a national level: A country case series

Viral hepatitis is a leading cause of morbidity and mortality worldwide, but has long been neglected by national and international policymakers. Recent modelling studies suggest that investing in the global elimination of viral hepatitis is feasible and cost-effective. In 2016, all 194 member states of the World Health Organization endorsed the goal to eliminate viral hepatitis as a public health threat by 2030, but complex systemic and social realities hamper implementation efforts. This paper presents eight case studies from a diverse range of countries that have invested in responses to viral hepatitis and adopted innovative approaches to tackle their respective epidemics. Based on an investment framework developed to build a global investment case for the elimination of viral hepatitis by 2030, national activities and key enablers are highlighted that showcase the feasibility and impact of concerted hepatitis responses across a range of settings, with different levels of available resources and infrastructural development. These case studies demonstrate the utility of taking a multipronged, public health approach to: (a) evidence-gathering and planning; (b) implementation; and (c) integration of viral hepatitis services into the Agenda for Sustainable Development. They provide models for planning, investment and implementation strategies for other countries facing similar challenges and resource constraints.

Evaluating the population impact of hepatitis C direct acting antiviral treatment as prevention for people who inject drugs (EPIToPe) - a natural experiment (protocol)

INTRODUCTION

Hepatitis C virus (HCV) is the second largest contributor to liver disease in the UK, with injecting drug use as the main risk factor among the estimated 200 000 people currently infected. Despite effective prevention interventions, chronic HCV prevalence remains around 40% among people who inject drugs (PWID). New direct-acting antiviral (DAA) HCV therapies combine high cure rates (>90%) and short treatment duration (8 to 12 weeks). Theoretical mathematical modelling evidence suggests HCV treatment scale-up can prevent transmission and substantially reduce HCV prevalence/incidence among PWID. Our primary aim is to generate empirical evidence on the effectiveness of HCV 'Treatment as Prevention' (TasP) in PWID.

METHODS AND ANALYSIS

We plan to establish a natural experiment with Tayside, Scotland, as a single intervention site where HCV care pathways are being expanded (including specialist drug treatment clinics, needle and syringe programmes (NSPs), pharmacies and prison) and HCV treatment for PWID is being rapidly scaled-up. Other sites in Scotland and England will act as potential controls. Over 2 years from 2017/2018, at least 500 PWID will be treated in Tayside, which simulation studies project will reduce chronic HCV prevalence among PWID by 62% (from 26% to 10%) and HCV incidence will fall by approximately 2/3 (from 4.2 per 100 person-years (p100py) to 1.4 p100py). Treatment response and re-infection rates will be monitored. We will conduct focus groups and interviews with service providers and patients that accept and decline treatment to identify barriers and facilitators in implementing TasP. We will conduct longitudinal interviews with up to 40 PWID to assess whether successful HCV treatment alters their perspectives on and engagement with drug treatment and recovery. Trained peer researchers will be involved in data collection and dissemination. The primary outcome - chronic HCV prevalence in PWID - is measured using information from the Needle Exchange Surveillance Initiative survey in Scotland and the Unlinked Anonymous Monitoring Programme in England, conducted at least four times before and three times during and after the intervention. We will adapt Bayesian synthetic control methods (specifically the Causal Impact Method) to generate the cumulative impact of the intervention on chronic HCV prevalence and incidence. We will use a dynamic HCV transmission and economic model to evaluate the cost-effectiveness of the HCV TasP intervention, and to estimate the contribution of the scale-up in HCV treatment to observe changes in HCV prevalence. Through the qualitative data we will systematically explore key mechanisms of TasP real world implementation from provider and patient perspectives to develop a manual for scaling up HCV treatment in other settings. We will compare qualitative accounts of drug treatment and recovery with a 'virtual cohort' of PWID linking information on HCV treatment with Scottish Drug treatment databases to test whether DAA treatment improves drug treatment outcomes.

ETHICS AND DISSEMINATION

Extending HCV community care pathways is covered by ethics (ERADICATE C, ISRCTN27564683, Super DOT C Trial clinicaltrials.gov: NCT02706223). Ethical approval for extra data collection from patients including health utilities and qualitative interviews has been granted (REC ref: 18/ES/0128) and ISCRCTN registration has been completed (ISRCTN72038467). Our findings will have direct National Health Service and patient relevance; informing prioritisation given to early HCV treatment for PWID. We will present findings to practitioners and policymakers, and support design of an evaluation of HCV TasP in England.

Randomised controlled trial conducted in injecting equipment provision sites to compare the effectiveness of different hepatitis C treatment regimens in people who inject drugs: A Direct obserVed therApy versus fortNightly CollEction study for HCV treatment-ADVANCE HCV protocol study

INTRODUCTION

Hepatitis C is a blood-borne virus (HCV) that can seriously damage the liver and is spread mainly through blood-to-blood contact with an infected person. Over 85% of individuals who have HCV in Scotland became infected following injecting drug use. Since people who inject drugs (PWID) are the main source of new infections, theoretical modelling has suggested that treatment of HCV infection in PWID may effectively reduce HCV prevalence and accomplish elimination. This protocol describes a clinical trial delivering HCV treatment within injecting equipment provision sites (IEPS) in Tayside, Scotland.

METHODS AND ANALYSIS

PWID attending IEPS are tested for HCV and, if they are chronically infected with HCV and eligible, invited to receive treatment within the IEPS. They are randomised to one of three treatment regimens; daily observed treatment, treatment dispensed every 2 weeks and treatment dispensed every 2 weeks together with an adherence psychological intervention (administered before treatment begins). The primary outcome is comparison of the rate of successful treatment (SVR12) in each treatment group. Secondary analyses include assessment of adherence, reinfection rates, viral resistance to treatment and interaction of the treatment with illicit drugs.

ETHICS AND DISSEMINATION

The ADVANCE (A Direct obserVed therApy versus fortNightly CollEction) HCV trial was given favourable opinion by East of Scotland Research Ethics Committee (LR/17/ES/0089) prior to commencement.

TRIAL REGISTRATION NUMBERS

European Clinical Trials Database (EudraCT) (2017-001039-38) and ClinicalTrials.gov (NCT03236506).

Transitioning from interferon-based to direct antiviral treatment options: A potential shift in barriers and facilitators of treatment initiation among people who use drugs?

BACKGROUND

Multiple barriers for accessing hepatitis C virus (HCV) treatment were identified during the interferon-based (IFN) treatment era for people who inject drugs (PWID). Whether these barriers persist since the introduction of IFN-free direct-acting antiviral (DAA) agents in Canada remains to be documented. This study examined temporal trends in HCV treatment initiation and associated factors during the transition from INF-based to all-oral DAA regimens.

METHODS

The study population was drawn from a prospective cohort of PWID in Montreal, Canada. At three-month/one-year intervals between 2011 and 2017, participants with chronic HCV infection completed an interviewer-administered questionnaire on socio-demographic characteristics, drug use and health service utilisation, including HCV treatment. Time-updated Cox multivariate regression models, stratified by DAA + INF (2011-2013) and all-oral DAA (2014-2017) availability periods, were conducted to examine associations between time to HCV treatment initiation and associated barriers and facilitators.

RESULTS

Of 308 participants (85% male, median age 42 [IQR: 33, 50]), 80 (26%) initiated HCV treatment during 915 person-years (PY). Incidence rates increased from 1.6 /100 PY (95%CI:0.9-2.6) in 2011 to 12.7 (10.6-15.1) in 2017 (p-trend = 0.0012). In multivariate analyses, visiting a primary care physician (2011-2013: aHR = 3.63[1.21-10.9]; 2014-2017: 2.52[1.10-5.77]) and frequent injection (0.23[0.05-0.99] and 0.49[0.24-0.99]) were consistently associated with treatment initiation. Participants aged >40 (2.27[1.24-4.13]), receiving opioid agonist therapy (OAT) (2.17[1.19-3.94]), and reporting prior HCV treatment (3.00[1.75-5.15]) were more likely to initiate treatment in the all-oral DAA period.

CONCLUSION

Treatment initiation increased between 2011 and 2017, but still remains low among PWID. Primary care visiting was a key facilitator regardless of the period, while engagement in OAT and health services, indicated by prior HCV treatment, increased the likelihood of treatment initiation in the DAA era. These findings suggest that access to health services is essential but not enough to scale up treatment in this population.

Hepatitis C transmission in young people who inject drugs: Insights using a dynamic model informed by state public health surveillance

Increasing injection of heroin and prescription opioids have led to increases in the incidence of hepatitis C virus (HCV) infections in US young adults since the early 2000s. How best to interrupt transmission and decrease HCV prevalence in young people who inject drugs (PWID) is uncertain. We developed an age-stratified ordinary differential equation HCV transmission model of PWID aged 15-64, which we fit to Michigan HCV surveillance data among young PWID aged 15-29. We used Latin hypercube sampling to fit to data under 10,000 plausible model parameterizations. We used the best-fitting 10% of simulations to predict the potential impact of primary (reducing injection initiation), secondary (increasing cessation, reducing injection partners, or reducing injection drug use relapse), and tertiary (HCV treatment) interventions (over the period 2017-2030) on acute and chronic HCV cases by the year 2030. Treating 3 per 100 current and former PWID per year could reduce chronic HCV by 27.3% (range: 18.7-30.3%) and acute HCV by 23.6% (range: 6.7-29.5%) by 2030 among PWID aged 15-29 if 90% are cured (i.e. achieved sustained virologic response [SVR] to treatment). Reducing the number of syringe sharing partners per year by 10% was predicted to reduce chronic HCV by 15.7% (range: 9.4-23.8%) and acute cases by 21.4% (range: 14.2-32.3%) among PWID aged 15-29 by 2030. In simulations of combinations of interventions, reducing injection initiation, syringe sharing, and relapse rates each by 10% while increasing cessation rates by 10% predicted a 27.7% (range: 18.0-39.7%) reduction in chronic HCV and a 38.4% (range: 28.3-53.3%) reduction in acute HCV. Our results highlight the need for HCV treatment among both current and former PWID and the scale up of both primary and secondary interventions to concurrently reduce HCV prevalence and incidence in Michigan.

Modelling the impact of a national scale-up of interventions on hepatitis C virus transmission among people who inject drugs in Scotland

BACKGROUND AND AIMS

To reduce hepatitis C virus (HCV) transmission among people who inject drugs (PWID), Scottish Government-funded national strategies, launched in 2008, promoted scaling-up opioid substitution therapy (OST) and needle and syringe provision (NSP), with some increases in HCV treatment. We test whether observed decreases in HCV incidence post-2008 can be attributed to this intervention scale-up.

DESIGN

A dynamic HCV transmission model among PWID incorporating intervention scale-up and observed decreases in behavioural risk, calibrated to Scottish HCV prevalence and incidence data for 2008/09.

SETTING

Scotland, UK.

PARTICIPANTS

PWID.

MEASUREMENTS

Model projections from 2008 to 2015 were compared with data to test whether they were consistent with observed decreases in HCV incidence among PWID while incorporating the observed intervention scale-up, and to determine the impact of scaling-up interventions on incidence.

FINDINGS

Without fitting to epidemiological data post-2008/09, the model incorporating observed intervention scale-up agreed with observed decreases in HCV incidence among PWID between 2008 and 2015, suggesting that HCV incidence decreased by 61.3% [95% credibility interval (CrI) = 45.1-75.3%] from 14.2/100 person-years (py) (9.0-20.7) to 5.5/100 py (2.9-9.2). On average, each model fit lay within 84% (10.1/12) of the confidence bounds for the 12 incidence data points against which the model was compared. We estimate that scale-up of interventions (OST + NSP + HCV treatment) and decreases in high-risk behaviour from 2008 to 2015 resulted in a 33.9% (23.8-44.6%) decrease in incidence, with the remainder [27.4% (17.6-37.0%)] explained by historical changes in OST + NSP coverage and risk pre-2008. Projections suggest that scaling-up of all interventions post-2008 averted 1492 (657-2646) infections over 7 years, with 1016 (308-1996), 404 (150-836) and 72 (27-137) due to scale-up of OST + NSP, decreases in high-risk behaviour and HCV treatment, respectively.

CONCLUSIONS

Most of the decline in hepatitis C virus (HCV) incidence in Scotland between 2008 and 2015 appears to be attributable to intervention scale-up (opioid substitution therapy and needle and syringe provision) due to government strategies on HCV and drugs.

Economically Efficient Hepatitis C Virus Treatment Prioritization Improves Health Outcomes

BACKGROUND

The total cost of treating the 3 million Americans chronically infected with hepatitis C virus (HCV) represents a substantial affordability challenge requiring treatment prioritization. This study compares the health and economic outcomes of alternative treatment prioritization schedules.

METHODS

We developed a multiyear HCV treatment budget allocation model to evaluate the tradeoffs of 7 prioritization strategies. We used optimization to identify the priority schedule that maximizes population net monetary benefit (NMB). We compared prioritization schedules in terms of the number of individuals treated, the number of individuals who progress to end-stage liver disease (ESLD), and population total quality-adjusted life years (QALYs). We applied the model to the population of treatment-naive patients with a total annual HCV treatment budget of US$8.6 billion.

RESULTS

First-come, first-served (FCFS) treats the fewest people with advanced fibrosis, prevents the fewest cases of ESLD, and gains the fewest QALYs. A schedule developed from optimizing population NMB prioritizes treatment in the first year to patients with moderate to severe fibrosis who are younger than 65 years, followed by older individuals with moderate to severe fibrosis. While this strategy yields the greatest population QALYs, prioritization by disease severity alone prevents more cases of ESLD. Sensitivity analysis indicated that the differences between prioritization schedules are greater when the budget is smaller. A 10% annual treatment price reduction enabled treatment 1 year sooner to several patient subgroups, specifically older patients and those with less severe liver fibrosis.

CONCLUSION

In the absence of a sufficient budget to treat all patients, explicit prioritization targeting younger people with more severe disease first provides the greatest health benefits. We provide our spreadsheet model so that decision makers can compare health tradeoffs of different budget levels and various prioritization strategies with inputs tailored to their population.

Quantifying potentially infectious sharing patterns among people who inject drugs in Baltimore, USA

Mixing matrices quantify how people with similar or different characteristics make contact with each other, creating potential for disease transmission. Little empirical data on mixing patterns among persons who inject drugs (PWID) are available to inform models of blood-borne disease such as HIV and hepatitis C virus. Egocentric drug network data provided by PWID in Baltimore, Maryland between 2005 and 2007 were used to characterise drug equipment-sharing patterns according to age, race and gender. Black PWID and PWID who were single (i.e. no stable sexual partner) self-reported larger equipment-sharing networks than their white and non-single counterparts. We also found evidence of assortative mixing according to age, gender and race, though to a slightly lesser degree in the case of gender. Highly assortative mixing according to race and gender highlights the existence of demographically isolated clusters, for whom generalised treatment interventions may have limited benefits unless targeted directly. These findings provide novel insights into mixing patterns of PWID for which little empirical data are available. The age-specific assortativity we observed is also significant in light of its role as a key driver of transmission for other pathogens such as influenza and tuberculosis.

A qualitative assessment of the acceptability of hepatitis C remote self-testing and self-sampling amongst people who use drugs in London, UK

Background

Hepatitis C (HCV) diagnosis and care is a major challenge for people who use illicit drugs, and is characterised by low rates of testing and treatment engagement globally. New approaches to fostering engagement are needed. We explored the acceptability of remote forms of HCV testing including self-testing and self-sampling among people who use drugs in London, UK.

Methods

A qualitative rapid assessment was undertaken with people who use drugs and stakeholders in London, UK. Focus groups were held with men who have sex with men engaged in drug use, people who currently inject drugs and people who formerly injected drugs (22 participants across the 3 focus groups). Stakeholders participated in semi-structured interviews (n = 5). We used a thematic analysis to report significant themes in participants’ responses.

Results

We report an overarching theme of ‘tension’ in how participants responded to the acceptability of remote testing. This tension is evident across four separate sub-themes we explore. First, choice and control, with some valuing the autonomy and privacy remote testing could support. Second, the ease of use of self testing linked to its immediate result and saliva sample was preferred over the delayed result from a self administered blood sample tested in a laboratory. Third, many respondents described the need to embed remote testing within a supportive care pathway. Fourth, were concerns over managing a positive result, and its different meanings, in isolation.

Conclusions

The concept of remote HCV testing is acceptable to some people who use drugs in London, although tensions with lived experience of drug use and health system access limit its relevance. Future development of remote testing must respond to concerns raised in order for acceptable implementation to take place.

Cost-effectiveness of diagnostic and therapeutic interventions for chronic hepatitis C: a systematic review of model-based analyses

BACKGROUND

Decisions about which subgroup of chronic hepatitis C (CHC) patients should be treated with direct acting anti-viral agents (DAAs) have economic importance due to high drug prices. Treat-all DAA strategies for CHC have gained acceptance despite high drug acquisition costs. However, there are also costs associated with the surveillance of CHC to determine a subgroup of patients with significant impairment. The aim of this systematic review was to describe the modelling methods used and summarise results in cost-effectiveness analyses (CEAs) of both CHC treatment with DAAs and surveillance of liver disease.

METHODS

Electronic databases including Embase and Medline were searched from inception to May 2015. Eligible studies included models predicting costs and/or outcomes for interventions, surveillance, or management of people with CHC. Narrative and quantitative synthesis were conducted. Quality appraisal was conducted using validated checklists. The review was conducted following principles published by NHS Centre for Research and Dissemination.

RESULTS

Forty-one CEAs met the eligibility criteria for the review; 37 evaluated an intervention and four evaluated surveillance strategies for targeting DAA treatment to those likely to gain most benefit. Included studies were of variable quality mostly due to reporting omissions. Of the 37 CEAs, eight models that enabled comparative analysis were fully appraised and synthesized. These models provided non-unique cost-effectiveness estimates in a specific DAA comparison in a specific population defined in terms of genotype, prior treatment status, and presence or absence of cirrhosis. Marked heterogeneity in cost-effectiveness estimates was observed despite this stratification. Approximately half of the estimates suggested that DAAs were cost-effective considering a threshold of US$30,000 and 73% with threshold of US$50,000. Two models evaluating surveillance strategies suggested that treating all CHC patients regardless of the staging of liver disease could be cost-effective.

CONCLUSIONS

CEAs of CHC treatments need to better account for variability in their estimates. This analysis suggested that there are still circumstances where DAAs are not cost-effective. Surveillance in place of a treat-all strategy may still need to be considered as an option for deploying DAAs, particularly where acquisition cost is at the limit of affordability for a given health system.

Population Health and Cost-Effectiveness Implications of a "Treat All" Recommendation for HCV: A Review of the Model-Based Evidence

The World Health Organization HCV Guideline Development Group is considering a "treat all" recommendation for persons infected with hepatitis C virus (HCV). We reviewed the model-based evidence of cost-effectiveness and population health impacts comparing expanded treatment policies to more limited treatment access policies, focusing primarily on evaluations of all-oral directly acting antivirals published after 2012. Searching PubMed, we identified 2,917 unique titles. Sequentially reviewing titles and abstracts identified 226 potentially relevant articles for full-text review. Sixty-nine articles met all inclusion criteria-42 cost-effectiveness analyses and 30 models of population-health impacts, with 3 articles presenting both types of analysis. Cost-effectiveness studies for many countries concluded that expanding treatment to people with mild liver fibrosis, who inject drugs (PWID), or who are incarcerated is generally cost-effective compared to more restrictive treatment access policies at country-specific prices. For certain patient subpopulations in some countries-for example, elderly individuals without fibrosis-treatment is only cost-effective at lower prices. A frequent limitation is the omission of benefits and consequences of HCV transmission (i.e., treatment as prevention; risks of reinfection), which may underestimate or overestimate the cost-effectiveness of a "treat all" policy. Epidemiologic modeling studies project that through a combination of prevention, aggressive screening and diagnosis, and prompt treatment for all fibrosis stages, it may be possible to virtually eliminate HCV in many countries. Studies show that if resources are not available to diagnose and treat all HCV-infected individuals, treatment prioritization may be needed, with alternative prioritization strategies resulting in tradeoffs between reducing mortality or reducing incidence. Notably, because most new HCV infections are among PWID in many settings, HCV elimination requires unrestricted treatment access combined with injection transmission disruption strategies. The model-based evidence suggests that a properly constructed strategy that substantially expands HCV treatment could achieve cost-effective improvements in population health in many countries.

Impact of new DAA therapy on real clinical practice: a multicenter region-wide cohort study

BACKGROUND

Management of chronic hepatitis C (CHC) has significantly accelerated in the last few years. Currently, second generation direct acting antivirals (DAAs) promise clearance of infection in most of patients. Here we present the results of the first analysis carried out on data of Lazio clinical network for DAAs.

METHODS

The study was designed as a multicenter cohort: a) to assess the evolution of treatment during the first 24 months of the activity of the Clinical Network; b) to report overall efficacy of treatments; c) to analyze potential factors associated with lack of virological response at 12 weeks after therapy (SVR12); d) to evaluate the variation of ALT at baseline and 12 weeks after therapy in those who achieved SVR12 in comparison to those who did not. Analyses of efficacy were carried out with multilevel mixed effect logistic regression model. ALT temporal variation was assessed by mixed effect model mixed models with random intercept at patient's level and random slope at the level of the time; i.e. either before or after therapy.

RESULTS

Between 30 December 2014 and 31 December 2016 5279 patients started a DAA treatment; of those, 5127 (in 14 clinical centers) had completed the 12-week follow-up. Overall proportion of SVR12 was 93.41% (N = 4780) with no heterogeneity between the 14 clinical centers. Interruption as the consequence of severe side effect was very low (only 23 patients). Unadjusted analysis indicates that proportion of SVR12 significantly changes according to patient's baseline characteristics, however after adjusting for potential confounders only adherence to current guidelines, stage of liver diseases, gender, transplant and HIV status were independently associated with the response to therapy. Analysis of ALT temporal variation showed that ALT level normalized in most, but not, all patients who achieved SVR12.

CONCLUSION

Our study confirmed the extraordinary efficacy of DAAs outside clinical trials. The advantage of DAAs was particularly significant for those patients who were previously considered as difficult-to-treat and did not have treatment options before DAAs era. Intervention based on network of select centers and prioritization of patients according to diseases severity was successful. Further studies are needed to establish whether clearance of HCV after DAAs therapy can arrest or even revert liver fibrosis in non-cirrhotic patients and/or improve life quality and expectancy in those who achieve SVR12 with cirrhosis.

Assessing uncertainty in the burden of hepatitis C virus: Comparison of estimated disease burden and treatment costs in the UK

Hepatitis C virus (HCV) is a major and growing public health concern. We need to know the expected health burden and treatment cost, and understand uncertainty in those estimates, to inform policymaking and future research. Two models that have been important in informing treatment guidelines and assessments of HCV burden were compared by simulating cohorts of individuals with chronic HCV infection initially aged 20, 35 and 50 years. One model predicts that health losses (measured in quality-adjusted life-years [QALYs]) and treatment costs decrease with increasing initial age of the patients, whilst the other model predicts that below 40 years, costs increase and QALY losses change little with age, and above 40 years, they decline with increasing age. Average per-patient costs differ between the models by up to 38%, depending on the patients' initial age. One model predicts double the total number, and triple the peak annual incidence, of liver transplants compared to the other model. One model predicts 55%-314% more deaths than the other, depending on the patients' initial age. The main sources of difference between the models are estimated progression rates between disease states and rates of health service utilization associated with different disease states and, in particular, the age dependency of these parameters. We conclude that decision-makers need to be aware that uncertainties in the health burden and economic cost of HCV disease have important consequences for predictions of future need for care and cost-effectiveness of interventions to avert HCV transmission, and further quantification is required to inform decisions.

Model projections on the impact of HCV treatment in the prevention of HCV transmission among people who inject drugs in Europe

BACKGROUND & AIMS

Prevention of hepatitis C virus (HCV) transmission among people who inject drugs (PWID) is critical for eliminating HCV in Europe. We estimated the impact of current and scaled-up HCV treatment with and without scaling up opioid substitution therapy (OST) and needle and syringe programmes (NSPs) across Europe over the next 10 years.

METHODS

We collected data on PWID HCV treatment rates, PWID prevalence, HCV prevalence, OST, and NSP coverage from 11 European settings. We parameterised an HCV transmission model to setting-specific data that project chronic HCV prevalence and incidence among PWID.

RESULTS

At baseline, chronic HCV prevalence varied from <25% (Slovenia/Czech Republic) to >55% (Finland/Sweden), and <2% (Amsterdam/Hamburg/Norway/Denmark/Sweden) to 5% (Slovenia/Czech Republic) of chronically infected PWID were treated annually. The current treatment rates using new direct-acting antivirals (DAAs) may achieve observable reductions in chronic prevalence (38-63%) in 10 years in Czech Republic, Slovenia, and Amsterdam. Doubling the HCV treatment rates will reduce prevalence in other sites (12-24%; Belgium/Denmark/Hamburg/Norway/Scotland), but is unlikely to reduce prevalence in Sweden and Finland. Scaling-up OST and NSP to 80% coverage with current treatment rates using DAAs could achieve observable reductions in HCV prevalence (18-79%) in all sites. Using DAAs, Slovenia and Amsterdam are projected to reduce incidence to 2 per 100 person years or less in 10 years. Moderate to substantial increases in the current treatment rates are required to achieve the same impact elsewhere, from 1.4 to 3 times (Czech Republic and France), 5-17 times (France, Scotland, Hamburg, Norway, Denmark, Belgium, and Sweden), to 200 times (Finland). Scaling-up OST and NSP coverage to 80% in all sites reduces treatment scale-up needed by 20-80%.

CONCLUSIONS

The scale-up of HCV treatment and other interventions is needed in most settings to minimise HCV transmission among PWID in Europe.

LAY SUMMARY

Measuring the amount of HCV in the population of PWID is uncertain. To reduce HCV infection to minimal levels in Europe will require scale-up of both HCV treatment and other interventions that reduce injecting risk (especially OST and provision of sterile injecting equipment).

Availability of hepatitis C diagnostics and therapeutics in European and Eurasia countries

BACKGROUND

Treatment with direct acting antiviral agents (DAAs) has provided sustained virological response rates in >95% of patients with chronic hepatitis C virus (HCV) infection. However treatment is costly and market access, reimbursement and governmental restrictions differ among countries. We aimed to analyze these differences among European and Eurasian countries.

METHODS

A survey including 20-item questionnaire was sent to experts in viral hepatitis. Countries were evaluated according to their income categories by the World Bank stratification.

RESULTS

Experts from 26 countries responded to the survey. As of May 2016, HCV prevalence was reported as low (≤1%) in Croatia, Czech Republic, Denmark, France, Germany, Hungary, the Netherlands, Portugal, Slovenia, Spain, Sweden, UK; intermediate (1-4%) in Azerbaijan, Bosnia and Herzegovina, Italy, Kosovo, Greece, Kazakhstan, Romania, Russia, Serbia and high in Georgia (6.7%). All countries had national guidelines except Albania, Kosovo, Serbia, Tunisia, and UK. Transient elastography was available in all countries, but reimbursed in 61%. HCV-RNA was reimbursed in 81%. PegIFN/RBV was reimbursed in 54% of the countries. No DAAs were available in four countries: Kazakhstan, Kosovo, Serbia, and Tunisia. In others, at least one DAA combination with either PegIFN/RBV or another DAA was available. In Germany and the Netherlands all DAAs were reimbursed without restrictions: Sofosbuvir and sofosbuvir/ledipasvir were free of charge in Georgia.

CONCLUSION

Prevalence of HCV is relatively higher in lower-middle and upper-middle income countries. DAAs are not available or reimbursed in many Eurasia and European countries. Effective screening and access to care are essential for reducing liver-related morbidity and mortality.

Hepatitis C disease transmission and treatment uptake: impact on the cost-effectiveness of new direct-acting antiviral therapies

BACKGROUND

Hepatitis C virus (HCV) treatment can reduce the incidence of future infections through removing opportunities for onward transmission. This benefit is not captured in conventional cost-effectiveness evaluations of treatment and is particularly relevant in patient groups with a high risk of transmission, such as those people who inject drugs (PWID), where the treatment rates have been historically low. This study aimed to quantify how reduced HCV transmission changes the cost-effectiveness of new direct-acting antiviral (DAA) regimens as a function of treatment uptake rates.

METHODS

An established model of HCV disease transmission and progression was used to quantify the impact of treatment uptake (10-100%), within the PWID population, on the cost-effectiveness of a DAA regimen versus pre-DAA standard of care, conducted using daclatasvir plus sofosbuvir in the UK setting as an illustrative example.

RESULTS

The consequences of reduced disease transmission due to treatment were associated with additional net monetary benefit of £24,304-£90,559 per patient treated at £20,000/QALY, when 10-100% of eligible patients receive treatment with 100% efficacy. Dependent on patient genotype, the cost-effectiveness of HCV treatment using daclatasvir plus sofosbuvir improved by 36-79% versus conventional analysis, at 10-100% treatment uptake in the PWID population.

CONCLUSIONS

The estimated cost-effectiveness of HCV treatment was shown to improve as more patients are treated, suggesting that the value of DAA regimens to the NHS could be enhanced by improved treatment uptake rates among PWID. However, the challenge for the future will lie in achieving increased rates of treatment uptake, particularly in the PWID population.

Hepatitis C bio-behavioural surveys in people who inject drugs-a systematic review of sensitivity to the theoretical assumptions of respondent driven sampling

BACKGROUND

New, more effective and better-tolerated therapies for hepatitis C (HCV) have made the elimination of HCV a feasible objective. However, for this to be achieved, it is necessary to have a detailed understanding of HCV epidemiology in people who inject drugs (PWID). Respondent-driven sampling (RDS) can provide prevalence estimates in hidden populations such as PWID. The aims of this systematic review are to identify published studies that use RDS in PWID to measure the prevalence of HCV, and compare each study against the STROBE-RDS checklist to assess their sensitivity to the theoretical assumptions underlying RDS.

METHOD

Searches were undertaken in accordance with PRISMA systematic review guidelines. Included studies were English language publications in peer-reviewed journals, which reported the use of RDS to recruit PWID to an HCV bio-behavioural survey. Data was extracted under three headings: (1) survey overview, (2) survey outcomes, and (3) reporting against selected STROBE-RDS criteria.

RESULTS

Thirty-one studies met the inclusion criteria. They varied in scale (range 1-15 survey sites) and the sample sizes achieved (range 81-1000 per survey site) but were consistent in describing the use of standard RDS methods including: seeds, coupons and recruitment incentives. Twenty-seven studies (87%) either calculated or reported the intention to calculate population prevalence estimates for HCV and two used RDS data to calculate the total population size of PWID. Detailed operational and analytical procedures and reporting against selected criteria from the STROBE-RDS checklist varied between studies. There were widespread indications that sampling did not meet the assumptions underlying RDS, which led to two studies being unable to report an estimated HCV population prevalence in at least one survey location.

CONCLUSION

RDS can be used to estimate a population prevalence of HCV in PWID and estimate the PWID population size. Accordingly, as a single instrument, it is a useful tool for guiding HCV elimination. However, future studies should report the operational conduct of each survey in accordance with the STROBE-RDS checklist to indicate sensitivity to the theoretical assumptions underlying the method.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015019245.

Modelling the impact of incarceration and prison-based hepatitis C virus (HCV) treatment on HCV transmission among people who inject drugs in Scotland

BACKGROUND AND AIMS

People who inject drugs (PWID) experience high incarceration rates, and previous incarceration is associated with elevated hepatitis C virus (HCV) transmission risk. In Scotland, national survey data indicate lower HCV incidence in prison than the community (4.3 versus 7.3 per 100 person-years), but a 2.3-fold elevated transmission risk among recently released (< 6 months) PWID. We evaluated the contribution of incarceration to HCV transmission among PWID and the impact of prison-related prevention interventions, including scaling-up direct-acting antivirals (DAAs) in prison.

DESIGN

Dynamic mathematical modelling of incarceration and HCV transmission, using approximate Bayesian computation for model calibration.

SETTING

Scotland, UK.

PARTICIPANTS

A simulated population of PWID.

MEASUREMENTS

Population-attributable fraction (PAF) of incarceration to HCV transmission among PWID. Decrease in HCV incidence and chronic prevalence due to current levels of prison opiate substitution therapy (OST; 57% coverage) and HCV treatment, as well as scaling-up DAAs in prison and/or preventing the elevated risk associated with prison release.

FINDINGS

Incarceration contributes 27.7% [PAF; 95% credible interval (CrI) -3.1 to 51.1%] of HCV transmission among PWID in Scotland. During the next 15 years, current HCV treatment rates (10.4/6.8 per 1000 incarcerated/community PWID annually), with existing prison OST, could reduce incidence and chronic prevalence among all PWID by a relative 10.7% (95% CrI = 8.4-13.3%) and 9.7% (95% CrI = 7.7-12.1%), respectively. Conversely, without prison OST, HCV incidence and chronic prevalence would decrease by 3.1% (95% CrI = -28.5 to 18.0%) and 4.7% (95% CrI = -11.3 to 14.5%). Additionally, preventing the heightened risk among recently released PWID could reduce incidence and chronic prevalence by 45.0% (95% CrI = 19.7-57.5%) and 33.3% (95% CrI = 15.6-43.6%) or scaling-up prison HCV treatments to 80% of chronic PWID prison entrants with sufficient sentences (>16 weeks) could reduce incidence and prevalence by 45.6% (95% CrI = 38.0-51.3%) and 45.5% (95% CrI = 39.3-51.0%), respectively.

CONCLUSIONS

Incarceration and the elevated transmission risk following prison release can contribute significantly to hepatitis C virus transmission among people who inject drugs. Scaling-up hepatitis C virus treatment in prison can provide important prevention benefits.

Real-world challenges for hepatitis C virus medications: a critical overview

From 2010, the landscape of hepatitis C therapeutics has been changed rapidly, and today we are standing at a cusp of a pharmacological revolution where highly effective and interferon (IFN)-free direct acting antivirals (DAAs) are already on the market. Such treatment paradigms attain 90-95% sustained virologic response (SVR; undetectable viral load at week 12 or 24 at the end of therapy) rates in treated individuals compared to 50-70% with treatment completion of dual-therapy-pegylated interferon (PEG-IFN) and ribavirin (RBV). As the major goal now for the hepatologists, clinicians, physicians, and health care workers is likely to eradicate hepatitis C infection in parallel to treatment, the demand is for a one-size-fits-all pill that could be prescribed beyond the limitations of hepatitis C genotype, viral load, previous treatment history, advanced hepatic manifestations (fibrosis, cirrhosis) and antiviral drug resistance. Although the new treatment strategies have shown high cure rates in clinical trials, such treatment paradigms are posing dilemmas too in real-world clinical practice. Therapy cost, treatment access to low and middle-income countries, treatment-emergent adverse events, lack of effective viral screening and disease progression simulation models are potential challenges in this prospect. This review article deeply overviews the challenges encountered while surmounting the burden of hepatitis C around the world.

Managing expense and expectation in a treatment revolution: Problematizing prioritisation through an exploration of hepatitis C treatment 'benefit'

BACKGROUND

Direct-acting antivirals (DAAs) have transformed the hepatitis C (HCV) treatment landscape. These highly effective drugs are, however, not available to all. In a context of DAA rationing, clinicians are advised to "manage patient expectations" about the benefits of a HCV cure. This directive particularly pertains to people with minimal liver damage and those who have ceased injecting: populations negated in contemporary prioritisation debates.

METHODS

This paper engages with the assumptions underpinning HCV treatment prioritisation discourses to explore the concept of treatment 'benefit' from patient perspectives. Data are from a qualitative longitudinal study exploring treatment transitions and decision-making from 2012-2015. Participants comprised 28 people living with HCV, ten treatment providers and eight stakeholders, based in London, United Kingdom (UK). One hundred hours of clinic observations were conducted at two HCV treatment hospitals. Thematic analyses pertaining to treatment expectation and outcome inform this paper.

RESULTS

Twenty-two participants commenced treatment. The majority who were unable to access DAAs chose to commence interferon-based treatment immediately rather than wait. Participants accounted for treatment urgency in relation to three interrelated narratives of hope and expectation. HCV treatment promised: social reconnection; social redemption and a return to 'normality'. For many with successful treatment outcomes, these benefits appeared to be realised.

CONCLUSION

The DAA era heralds a discursive shift: from 'managing [interferon] risk and difficulty' to 'managing [DAA] expense and expectation'. Calls to 'manage patient expectations' about the benefits of HCV cure are predicated on clinical benefits only, negating the social impacts of living with HCV. The public health priorities commonly articulated in treatment prioritisation debates are not consistent with those of people managing illness in their daily lives. During this 'treatment revolution' there is a need to be cognisant of the multiple publics living with the virus and the treatment needs of those who do not fit population-health scenarios.

A New Paradigm in Gallstones Diseases and Marked Elevation of Transaminases: An Observational Study

BACKGROUND

In clinical practice, it is assumed that a severe rise in transaminases is caused by ischemic, viral or toxic hepatitis. Nevertheless, cases of biliary obstruction have increasingly been associated with significant hypertransaminemia. With this study, we sought to determine the true etiology of marked rise in transaminases levels, in the context of an emergency department.

MATERIAL AND METHODS

We retrospectively identified all patients admitted to the emergency unit at Centro Hospitalar e Universitário de Coimbra between 1st January 2010 and 31st December 2010, displaying an increase of at least one of the transaminases by more than 15 times. All patient records were analyzed in order to determine the cause of hypertransaminemia.

RESULTS

We analyzed 273 patients - 146 males, mean age 65.1 ± 19.4 years. The most frequently etiology found for marked hypertransaminemia was pancreaticobiliary acute disease (n = 142;39.4%), mostly lithiasic (n = 113;79.6%), followed by malignancy (n = 74;20.6%), ischemic hepatitis (n = 61;17.0%), acute primary hepatocellular disease (n = 50;13.9%) and muscle damage (n = 23;6.4%). We were not able to determine a diagnosis for 10 cases. There were 27 cases of recurrence in the lithiasic pancreaticobiliary pathology group. Recurrence was more frequent in the group of patients who had not been submitted to early cholecystectomy after the first episode of biliary obstruction (p = 0.014). The etiology of hypertransaminemia varied according to age, cholestasis and glutamic-pyruvic transaminase values.

CONCLUSION

Pancreaticobiliary lithiasis is the main cause of marked hypertransaminemia. Hence, it must be considered when dealing with such situations. Not performing cholecystectomy early on, after the first episode of biliary obstruction, may lead to recurrence.

Value of Sustained Virologic Response in Patients with Hepatitis C as a Function of Time to Progression of End-Stage Liver Disease

BACKGROUND

Targeted intervention in patients with hepatitis C virus (HCV) closest to end-stage liver disease (ESLD) progression may offer an approach to treatment prioritisation whilst delivering benefits for patients and the healthcare system. In contrast to previous HCV economic analyses, this study aimed to estimate the health economic value of sustained virologic response (SVR) stratified by the patient's propensity to progress to ESLD.

METHODS

An HCV natural history model was adapted to estimate the value of avoiding ESLD complications following SVR, assessed as cost offsets and quality-adjusted life year (QALY) gains, as a function of time to ESLD at treatment initiation. These outcomes were used to estimate the financial value of achieving SVR, defined as the maximum investment that could be allocated without exceeding a willingness-to-pay threshold of £20,000/QALY.

RESULTS

Regardless of time to ESLD onset, achieving SVR was beneficial, resulting in cost offsets and QALY gains, due to avoidance of ESLD complications. The value of achieving SVR was greatest in patients closest to ESLD onset, resulting in increased cost offsets and QALY gains (up to £50,901 and 9.56 QALYs). In patients closest to ESLD onset, the financial value of achieving SVR was £242,051, compared with £127,116 in patients furthest from onset.

CONCLUSIONS

Standard cost-effectiveness evaluations may underestimate the value of treatment in HCV patients closest to ESLD development. Targeted intervention would promote efficient allocation of limited healthcare resources and reconcile concerns surrounding the affordability of new direct-acting antivirals, by minimising the number-needed-to-treat to maximise health benefit, whilst minimising healthcare expenditure.

Eradication of Hepatitis C Virus Infection in Patients With Cirrhosis Reduces Risk of Liver and Non-Liver Complications

BACKGROUND & AIMS

We performed a prospective study to investigate the effects of a sustained viral response (SVR) on outcomes of patients with hepatitis C virus (HCV) infection and compensated cirrhosis.

METHODS

We collected data from 1323 patients included in the prospective Agence Nationale pour la Recherche sur le SIDA et les hépatites virales (ANRS) viral cirrhosis (CirVir) cohort, recruited from 35 clinical centers in France from 2006 through 2012. All patients had HCV infection and biopsy-proven cirrhosis, were Child-Pugh class A, and had no prior liver complications. All patients received anti-HCV treatment before or after inclusion (with interferon then with direct antiviral agents) and underwent an ultrasound examination every 6 months, as well as endoscopic evaluations. SVR was considered as a time-dependent covariate; its effect on outcome was assessed by the Cox proportional hazard regression method. We used a propensity score to minimize confounding by indication of treatment and capacity to achieve SVR.

RESULTS

After a median follow-up period of 58.2 months, 668 patients (50.5%) achieved SVR. SVR was associated with a decreased incidence of hepatocellular carcinoma (hazard ratio [HR] compared with patients without an SVR, 0.29; 95% confidence interval [CI], 0.19-0.43; P < .001) and hepatic decompensation (HR, 0.26; 95% CI, 0.17-0.39; P < .001). Patients with SVRs also had a lower risk of cardiovascular events (HR, 0.42; 95% CI, 0.25-0.69; P = .001) and bacterial infections (HR, 0.44; 95% CI, 0.29-0.68; P < .001). Metabolic features were associated with a higher risk of hepatocellular carcinoma in patients with SVRs, but not in patients with viremia. SVR affected overall mortality (HR, 0.27 compared with patients without SVR; 95% CI, 0.18-0.42; P < .001) and death from liver-related and non-liver-related causes. Similar results were obtained in a propensity score-matched population.

CONCLUSIONS

We confirmed a reduction in critical events, liver-related or not, in a prospective study of patients with HCV infection and compensated cirrhosis included in the CirVir cohort who achieved an SVR. We found an SVR to reduce overall mortality and risk of death from liver-related and non-liver-related causes. A longer follow-up evaluation is required to accurately describe and assess specific risk factors for complications in this population.

Tackling the burden of the hepatitis C virus in the UK: characterizing and assessing the clinical and economic consequences

OBJECTIVES

The hepatitis C virus (HCV) remains a significant public health issue. This study aimed to quantify the clinical and economic burden of chronic hepatitis C in the UK, stratified by disease severity, age and awareness of infection, with concurrent assessment of the impact of implementing a treatment prioritization approach.

STUDY DESIGN AND METHODS

A previously published back projection, natural history and cost-effectiveness HCV model was adapted to a UK setting to estimate the disease burden of chronic hepatitis C and end-stage liver disease (ESLD) between 1980 and 2035. A published meta-regression analysis informed disease progression, and UK-specific data informed other model inputs.

RESULTS

At 2015, prevalence of chronic hepatitis C is estimated to be 241,487 with 22.20%, 33.72%, 17.22%, 16.67% and 10.19% of patients in METAVIR stages F0, F1, F2, F3 and F4, respectively, but is estimated to fall to 193,999 by 2035. ESLD incidence is predicted to peak in 2031. Assuming all patients are diagnosed and treatment is prioritized in F3 and F4 using highly efficacious direct-acting antiviral (DAA) regimens, a 69.85% reduction in ESLD incidence is predicted between 2015 and 2035, and the cumulative discounted medical expenditure associated with the lifetime management of incident ESLD events is estimated to be £1,202,827,444.

CONCLUSIONS

The prevalence of chronic hepatitis C is expected to fall in coming decades; however, the ongoing financial burden is expected to be high due to an increase in ESLD incidence. This study highlights the significant costs of managing ESLD that are likely to be incurred without the employment of effective treatment approaches.

Hepatitis C: global epidemiology and strategies for control

It is estimated that globally there are approximately 100 million persons with serological evidence of current or past HCV infection, and that HCV causes about 700 000 deaths each year. The prevalence of infection is the highest in lower and middle income countries, in which a significant number of past infections were caused by iatrogenic transmission and sub-optimal injection safety. In contrast, in developed countries, infections are caused mainly by high-risk exposures and behaviours among specific populations, such as persons who inject drugs. Recently, new direct antiviral activity (DAA) oral drugs with high rates of cure over short duration, which are well tolerated, have made chronic hepatitis C a curable condition. The extraordinary clinical performance of DAAs and recent substantial price reductions and expansion in access in resource-limited settings has provided new impetus for potential control and elimination of hepatitis C as a public health threat. We review the global epidemiology of HCV and the opportunities for preventative and treatment interventions to achieve global control of HCV infection. We also summarize the key elements of the World Health Organization's first-ever global health sector strategy for addressing the viral hepatitis pandemic.

Review article: treatment as prevention - targeting people who inject drugs as a pathway towards hepatitis C eradication

BACKGROUND

Hepatitis C virus (HCV) is a leading cause of chronic liver disease worldwide. HCV predominates in people who inject drugs; a group in whom anti-viral therapy has previously been withheld on the basis of chaotic lifestyles and associated risks of reinfection. New research has emerged which suggests that by specifically targeting HCV-infected people who inject drugs for treatment, the pool of HCV would deplete, thus reducing overall transmission and eventually leading to HCV eradication.

AIM

To outline the requirements for HCV eradication and review the evidence that this is achievable.

METHODS

Expert review of the literature.

RESULTS

The achievement of HCV eradication using 'treatment as prevention' is supported by numerous epidemiological modelling studies employing a variety of models in several contexts including people who inject drugs, men who have sex with men and prisoners. More recent studies also incorporate the newer, more efficacious direct-acting anti-viral drugs. These drugs have been shown to be safe and effective in people who inject drugs in clinical trials. There is no empirical evidence of the impact of treatment as prevention strategies on population prevalence.

CONCLUSIONS

This review highlights the efforts to control HCV and evaluates the possibilities of achieving eradication of HCV. Currently, the technologies required to achieve HCV eradication exist, but the infrastructure to deliver them is not generally available or of insufficient scale outside of specific areas. Such areas are yet to demonstrate that elimination is possible, but results of studies in these areas are awaited. Such a demonstration would be proof of principle for eradication. Although we are aspiring towards HCV eradication, elimination is the more realistic prospect.

Effects of Eradicating Hepatitis C Virus Infection in Patients With Cirrhosis Differ With Stage of Portal Hypertension

BACKGROUND & AIMS

Clearance of hepatitis C virus (HCV) via antiviral treatment changes the course of liver disease. We evaluated the benefit of sustained virologic response (SVR) in patients with HCV and cirrhosis without (stage 1) and with (stage 2) esophageal varices (EV).

METHODS

We performed a prospective cohort study of 444 patients with HCV and compensated cirrhosis (218 with stage 1 and 226 with stage 2 disease) treated with peg-interferon and ribavirin from June 2001 through December 2009 at the University of Palermo, Italy and followed for a median of 7.6 years (range, 1-12.6 years). We used Cox regression analysis to identify variables associated with appearance or progression of EVs, development of hepatocellular carcinoma (HCC), liver decompensation, and overall survival.

RESULTS

In the intention-to-treat analysis, 67 patients with stage 1 disease (30.7%) and 41 patients with stage 2 disease (18.1%) achieved an SVR (P = .003). Patients with stage 1 disease and an SVR were less likely to develop EVs than stage 1 patients without an SVR (hazard ratio [HR], 0.23; 95% confidence interval [CI], 0.11-0.48; P < .001). However, SVR did not affect whether patients with stage 2 disease developed further EVs (HR, 1.58; 95% CI, 0.33-1.03; P = .07, by log-rank test). An SVR was associated with lower risk for HCC (HR, 0.25; 95% CI, 0.12-0.55; P < .001). Patients with stage 2 disease, regardless of SVR, were at greater risk than patients with stage 1 disease for liver decompensation (HR, 2.82; 95% CI, 1.73-4.59; P < .001) or death (HR, 1.77; 95% CI, 1.12-2.80; P = .015). A lower proportion of patients with stage 1 disease and an SVR died from HCC (2.9%), compared with those without an SVR (11.9%) (P = .03) or developed liver decompensation (none vs 7.1% without an SVR; P = .009). A lower proportion of patients with stage 2 disease and an SVR died from causes secondary to HCC (2.0%) compared with those without an SVR (18.4%) (P = .003). Death from causes secondary to liver decompensation did not differ significantly between patients with stage 2 disease with or without an SVR (12.1% vs 25.4%; P = .15).

CONCLUSIONS

In a prospective study of 444 patients with HCV and compensated cirrhosis, HCV eradication reduced risk for liver decompensation, HCC, and death, regardless of whether the patients had EVs.

Urgent action to fight hepatitis C in people who inject drugs in Europe

Hepatitis C virus (HCV) infection is a leading cause of liver cirrhosis and liver cancer, is curable in most people. Injecting drug use currently accounts for 80 % of new HCV infections with a known transmission route in the European Union (EU). HCV has generally received little attention from the public or policymakers in the EU, with major gaps in national-level strategies, action plans, guidelines and the evidence base. Specifically, people who inject drugs (PWID) are often excluded from treatment owing to various patient, healthcare provider and health system factors. All policymakers responsible for health services in EU countries should ensure that prevention, treatment, care and support interventions addressing HCV in PWID are developed and implemented. According to current best practice, PWID should have access to comprehensive, evidence-based multiprofessional harm reduction (especially opioid substitution therapy and clean needles and syringes) and support/care services based in the community and modified with community involvement to accommodate this hard-to-reach population. Other recommended components of care include vaccination against hepatitis B and other infections; peer support interventions; HIV testing, prevention and treatment; drug and alcohol services; psychological care as needed; and social support services. HCV testing should be performed regularly in PWID to identify infected persons and engage them in care. HCV-infected PWID should be considered for antiviral treatment (based on an individualised assessment and delivered within multidisciplinary care/support programmes) both to cure infected individuals and prevent onward transmission. Modelling data suggest that the HCV disease burden can only be cut substantially if antiviral treatment is scaled up together with prevention programmes. Measures should be taken to reduce stigma and discrimination against PWID at the provider and institutional levels. In conclusion, strategic action at the policy level is urgently needed to increase access to HCV prevention, testing and treatment among PWID, the group at highest risk of HCV infection. Such action has the potential to substantially reduce the number of infected persons, along with the disease burden and related care costs.

Is increased hepatitis C virus case-finding combined with current or 8-week to 12-week direct-acting antiviral therapy cost-effective in UK prisons? A prevention benefit analysis

Prisoners have a high prevalence of hepatitis C virus (HCV), but case-finding may not have been cost-effective because treatment often exceeded average prison stay combined with a lack of continuity of care. We assessed the cost-effectiveness of increased HCV case-finding and treatment in UK prisons using short-course therapies. A dynamic HCV transmission model assesses the cost-effectiveness of doubling HCV case-finding (achieved through introducing opt-out HCV testing in UK pilot prisons) and increasing treatment in UK prisons compared to status quo voluntary risk-based testing (6% prison entrants/year), using currently recommended therapies (8-24 weeks) or interferon (IFN)-free direct-acting antivirals (DAAs; 8-12 weeks, 95% sustained virological response, £3300/week). Costs (British pounds, £) and health utilities (quality-adjusted life years) were used to calculate mean incremental cost-effectiveness ratios (ICERs). We assumed 56% referral and 2.5%/25% of referred people who inject drugs (PWID)/ex-PWID treated within 2 months of diagnosis in prison. PWID and ex-PWID or non-PWID are in prison an average 4 and 8 months, respectively. Doubling prison testing rates with existing treatments produces a mean ICER of £19,850/quality-adjusted life years gained compared to current testing/treatment and is 45% likely to be cost-effective under a £20,000 willingness-to-pay threshold. Switching to 8-week to 12-week IFN-free DAAs in prisons could increase cost-effectiveness (ICER £15,090/quality-adjusted life years gained). Excluding prevention benefit decreases cost-effectiveness. If >10% referred PWID are treated in prison (2.5% base case), either treatment could be highly cost-effective (ICER<£13,000). HCV case-finding and IFN-free DAAs could be highly cost-effective if DAA cost is 10% lower or with 8 weeks' duration.

CONCLUSIONS

Increased HCV testing in UK prisons (such as through opt-out testing) is borderline cost-effective compared to status quo voluntary risk-based testing under a £20,000 willingness to pay with current treatments but likely to be cost-effective if short-course IFN-free DAAs are used and could be highly cost-effective if PWID treatment rates were increased. (Hepatology 2016;63:1796-1808).

Immunization with a Recombinant Expression Vector Encoding NS3/NS4A of Hepatitis C Virus Genotype 3a Elicits Cell-Mediated Immune Responses in C57BL/6 Mice

Today, hepatitis C virus (HCV) infection is considered as one of the most significant international health concerns. Although novel therapeutic regimens against the infection have shown satisfactory results, no approved vaccine exists yet. This study aimed to evaluate the immunogenicity of a DNA vaccine candidate for HCV-3a, based on nonstructural proteins NS3/NS4A, in C57BL/6 mice. Immunogenicity effect of pDisplay-NS3/NS4A was analyzed through immunization with 100 and 200 μg concentrations of the construct with complete Freund's adjuvant, monophosphoryl lipid A (MPL), or without adjuvant. The frequencies of different splenic mononuclear cells were measured using the Mouse Th1/Th2/Th17 Phenotyping Kit. Moreover, the number of T-CD8(+) cells was determined using conjugated anti-CD8a and anti-CD3e antibodies by flow cytometry. As observed, the frequencies of Th1, T-CD8(+), and Th2 cells increased in all the experimental groups, compared with the controls. The highest levels of the respective cells were seen in the group immunized with 200 μg of the construct with MPL. Also, there were positive correlations between the frequency of Th1 cells and those of Th2 and T-CD8(+) cells in all the immunized groups, but were significant in those receiving adjuvants. The frequency of Th17 cells did not statistically change among the groups. Taken together, our findings revealed that the constructed DNA vaccine encoding HCV-3a NS3/NS4A gene induces the cell-mediated immune responses significantly. However, its coadministration with adjuvants exhibits more efficient results than the recombinant plasmid alone. Further study is currently underway to evaluate the specific immune responses and recognize the responsible antigenic epitopes.

Expression of NS3/NS4A Proteins of Hepatitis C Virus in Huh7 Cells Following Engineering Its Eukaryotic Expression Vector

BACKGROUND

Although the development of novel therapeutic regimens to combat hepatitis C virus (HCV) infection have been speeded up with successful results, no efficient vaccines exist yet.

OBJECTIVES

This study aimed to construct a eukaryotic expression vector encoding nonstructural proteins, NS3/NS4A, of HCV genotype 3a, and evaluate its expression on Huh7 cell surface.

MATERIALS AND METHODS

The NS3/NS4A sequence was isolated from a patient with HCV-3a chronic infection, cloned into intermediate vector pTZ57R/T, and then used for engineering a mammalian expression vector, pDisplay, to direct the respective protein to the secretory pathway and anchor it to the plasma membrane. The expression of the protein in Huh7 cell, which was transiently transfected with the vector using Lipofectamine, was determined by immunocytochemical staining assay with fluorescein isothiocyanate (FITC)-conjugated antibodies to the HA/myc tags located besides the fusion fragment.

RESULTS

The results showed that the fragment was successfully amplified and cloned into a eukaryotic expression vector. Sequencing and enzyme digestion analysis confirmed the cloned gene completion and its correct position in the pDisply-NS3/NS4A plasmid. Immunocytochemical staining revealed that the target protein was expressed as a membrane-anchored protein in the Huh7 cells.

CONCLUSIONS

This study can serve as a fundamental experiment for the construction of a NS3/NS4A eukaryotic expression vector and its expression in mammalian cells. Further research is underway to evaluate the fragment immunogenicity in lab animal models.

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.

Toward a more complete understanding of the association between a hepatitis C sustained viral response and cause-specific outcomes

Sustained viral response (SVR) is the optimal outcome of hepatitis C virus (HCV) therapy, yet more detailed data are required to confirm its clinical value. Individuals receiving treatment in 1996-2011 were identified using the Scottish HCV clinical database. We sourced data on 10 clinical events: liver, nonliver, and all-cause mortality; first hospitalisation for severe liver morbidity (SLM); cardiovascular disease (CVD); respiratory disorders; neoplasms; alcohol-intoxication; drug intoxication; and violence-related injury (note: the latter three events were selected a priori to gauge ongoing chaotic lifestyle behaviours). We determined the association between SVR attainment and each outcome event, in terms of the relative hazard reduction and absolute risk reduction (ARR). We tested for an interaction between SVR and liver disease severity (mild vs. nonmild), defining mild disease as an aspartate aminotransferase-to-platelet ratio index (APRI) <0.7. Our cohort comprised 3,385 patients (mean age: 41.6 years), followed-up for a median 5.3 years (interquartile range: 3.3-8.2). SVR was associated with a reduced risk of liver mortality (adjusted hazard ratio [AHR]: 0.24; P < 0.001), nonliver mortality (AHR, 0.68; P = 0.026), all-cause mortality (AHR, 0.49; P < 0.001), SLM (AHR, 0.21; P < 0.001), CVD (AHR, 0.70; P = 0.001), alcohol intoxication (AHR, 0.52; P = 0.003), and violence-related injury (AHR, 0.51; P = 0.002). After 7.5 years, SVR was associated with significant ARRs for liver mortality, all-cause mortality, SLM, and CVD (each 3.0%-4.7%). However, we detected a strong interaction, in that ARRs were considerably higher for individuals with nonmild disease than for individuals with mild disease.

CONCLUSIONS

The conclusions are 3-fold: (1) Overall, SVR is associated with reduced hazard for a range of hepatic and nonhepatic events; (2) an association between SVR and behavioral events is consistent with SVR patients leading healthier lives; and (3) the short-term value of SVR is greatest for those with nonmild disease.