Improving the accuracy of long-term prognostic estimates in hepatitis C virus infection

The impact of direct acting antivirals on hepatitis C virus disease burden and associated costs in four european countries

BACKGROUND AND AIMS

We assessed the clinical and economic impact of direct-acting antiviral (DAA) therapy for hepatitis C virus (HCV) in England, Italy, Romania and Spain.

METHODS

An HCV progression Markov model was developed considering DAA eligibility and population data during the years 2015-2019. The period of time to recover the investment in DAAs was calculated as the cost saved by avoiding estimated clinical events for 1000 standardized treated patients. A delayed treatment scenario because of coronavirus disease (COVID-19) was also developed.

RESULTS

The estimated number of avoided hepatocellular carcinoma, decompensated cirrhosis and liver transplantations over a 20-year time horizon was: 1,057 in England; 1,221 in Italy; 1,211 in Romania; and 1,103 in Spain for patients treated during 2015-2016 and 640 in England; 626 in Italy; 739 in Romania; and 643 in Spain for patients treated during 2017-2019. The cost-savings ranged from € 45 to € 275 million. The investment needed to expand access to DAAs in 2015-2019 is estimated to be recovered in 6.5 years in England; 5.4 years in Italy; 6.7 years in Romania; and 4.5 years in Spain. A delay in treatment because of COVID-19 will increase liver mortality in all countries.

CONCLUSION

Direct-acting antivirals have significant clinical benefits and can bring substantial cost-savings over the next 20 years, reaching a Break-even point in a short period of time. When pursuing an exit strategy from strict lockdown measures for COVID-19, providing DAAs should remain high on the list of priorities in order to maintain HCV elimination efforts.

Definition of the profiles of hepatitis C virus patients based on the identification of risky practices in Spain

The absolute number of patients infected with the hepatitis C virus and its prevalence in Spain according to risk practices are not precise. The objective of the study was to estimate the current direct-action antiviral candidates, according to risky practices. The exposed population was determined according to each risky practice and age, based on the data obtained in two epidemiological studies and other bibliographic sources. The overall prevalence of positive serology for the Hepatitis C virus according to the analyzed data was 1.1% (41% with an active infection). The most at-risk group are intravenous drug users (60,368-82,454). It is estimated that between 37,387 to 51,065 patients would be infected via sexual transmission, between 55,505 and 75,812 patients following a blood transfusion and around 18,528 to 25,307 patients by socio-family transmission. According to these data, more than half (55-79%) of the subjects with risky practices would have significant fibrosis (≥ F2). It is estimated that more than half a million people have a positive serology for the Hepatitis C virus and 144,191 to 227,773 antiviral treatments are expected in the coming years. The identification of people with risky practices is key to increase the percentage of diagnosed cases.

The health impact of delaying direct-acting antiviral treatment for chronic hepatitis C: A decision-analytic approach

BACKGROUND & AIMS

Direct-acting antivirals (DAAs) are highly effective, but expensive treatments for chronic hepatitis C (CHC). To manage costs, drug plans worldwide have rationed access to DAAs in a variety of ways. This study quantifies the health impact of formulary restrictions and presents a clinical decision tool for informing treatment timing decisions.

METHODS

A decision-analytic model was developed to quantify the health impact of delaying DAAs for subpopulations stratified by age, fibrosis level, viral genotype, and injection drug use over their lifetime. The health impact was quantified in terms of quality-adjusted life expectancy (quality-adjusted life years, or QALYs) and life expectancy (years).

RESULTS

Deferring DAAs for patients with no or mild fibrosis (F0/F1) for 1-5 years is unlikely to result in life expectancy losses and leads only to marginal losses of 0.02-0.06 QALYs per year of delay. However, for 30-50-year-olds with advanced fibrosis (≥F3) delays as short as a year results in a considerable health loss (0.25-1.04 QALYs and 0.19-1.53 years). Reimbursement limits for those with substance use are associated with large health losses. People who actively inject drugs with advanced fibrosis (≥F3) may lose 0.18-1.05 QALYs and 0.13-1.16 years per year of delay, despite the risk of reinfection and competing mortality. Results are robust to parameter uncertainty and key assumptions.

CONCLUSIONS

We present a clinical decision tool for informing treatment timing for various CHC subpopulations. In general, findings suggest that patients with at least moderate fibrosis should be treated promptly regardless of active drug use.

Estimation of fibrosis progression rates for chronic hepatitis C: a systematic review and meta-analysis update

OBJECTIVES

Mathematical models are increasingly important in planning for the upcoming chronic hepatitis C (CHC) elimination efforts. Such models require reliable natural history inputs to make accurate predictions on health and economic outcomes. Yet, hepatitis C virus disease progression is known to vary widely in the literature and published inputs are currently outdated. The objectives of this study were to obtain updated estimates of fibrosis progression rates (FPR) in treatment-naïve patients with CHC and to explore sources of heterogeneity.

DESIGN

A systematic review was conducted using Ovid-MEDLINE, Ovid-EMBASE and PubMed databases (January 1990 to January 2018) to identify observational studies of hepatic fibrosis in treatment-naïve patients with CHC.

OUTCOMES

Stage-constant FPRs were estimated for each study given the reported fibrosis scores and duration of infection. Stage-specific FPRs (ie, F0→F1; F1→F2; F2→F3; F3→F4) were estimated using Markov maximum likelihood estimation. Estimates were pooled using random-effects meta-analysis and heterogeneity was evaluated by stratification and random-effects meta-regression.

RESULTS

The review identified 111 studies involving 131 groups of patients (n=42 693). The pooled stage-constant FPR was 0.094 (95% CI 0.088 to 0.100); stage-specific FPRs were F0→F1: 0.107 (95% CI 0.097 to 0.118); F1→F2: 0.082 (95% CI 0.074 to 0.091); F2→F3: 0.117 (95% CI 0.107 to 0.129); F3→F4: 0.116 (95% CI 0.104 to 0.131). Stratified analysis revealed substantial variation in progression by study population. Meta-regression indicated associations between progression and infection age, duration, source, viral genotype and study population. Findings indicate that FPRs display substantial heterogeneity across study populations and pooled values from more homogenous subpopulations should be considered when estimating prognosis.

CONCLUSIONS

This large meta-analysis presents updated prognostic estimates for CHC derived from newer studies using better diagnostic methods and improves estimates for important patient populations in terms of clinical policy (eg, injection drug users, non-clinical populations, liver clinic patients) and should be a valuable resource for patients, clinicians and clinical policymakers.

Economic Consequences of Investing in Anti-HCV Antiviral Treatment from the Italian NHS Perspective: A Real-World-Based Analysis of PITER Data

OBJECTIVE

We estimated the cost consequence of Italian National Health System (NHS) investment in direct-acting antiviral (DAA) therapy according to hepatitis C virus (HCV) treatment access policies in Italy.

METHODS

A multistate, 20-year time horizon Markov model of HCV liver disease progression was developed. Fibrosis stage, age and genotype distributions were derived from the Italian Platform for the Study of Viral Hepatitis Therapies (PITER) cohort. The treatment efficacy, disease progression probabilities and direct costs in each health state were obtained from the literature. The break-even point in time (BPT) was defined as the period of time required for the cumulative costs saved to recover the Italian NHS investment in DAA treatment. Three different PITER enrolment periods, which covered the full DAA access evolution in Italy, were considered.

RESULTS

The disease stages of 2657 patients who consecutively underwent DAA therapy from January 2015 to December 2017 at 30 PITER clinical centres were standardized for 1000 patients. The investment in DAAs was considered to equal €25 million, €15 million, and €9 million in 2015, 2016, and 2017, respectively. For patients treated in 2015, the BPT was not achieved, because of the disease severity of the treated patients and high DAA prices. For 2016 and 2017, the estimated BPTs were 6.6 and 6.2 years, respectively. The total cost savings after 20 years were €50.13 and €55.50 million for 1000 patients treated in 2016 and 2017, respectively.

CONCLUSIONS

This study may be a useful tool for public decision makers to understand how HCV clinical and epidemiological profiles influence the economic burden of HCV.

Estimating chronic hepatitis C prognosis using transient elastography-based liver stiffness: A systematic review and meta-analysis

Chronic hepatitis C (CHC) is a leading cause of hepatic fibrosis and cirrhosis. The level of fibrosis is traditionally established by histology, and prognosis is estimated using fibrosis progression rates (FPRs; annual probability of progressing across histological stages). However, newer noninvasive alternatives are quickly replacing biopsy. One alternative, transient elastography (TE), quantifies fibrosis by measuring liver stiffness (LSM). Given these developments, the purpose of this study was (i) to estimate prognosis in treatment-naïve CHC patients using TE-based liver stiffness progression rates (LSPR) as an alternative to FPRs and (ii) to compare consistency between LSPRs and FPRs. A systematic literature search was performed using multiple databases (January 1990 to February 2016). LSPRs were calculated using either a direct method (given the difference in serial LSMs and time elapsed) or an indirect method given a single LSM and the estimated duration of infection and pooled using random-effects meta-analyses. For validation purposes, FPRs were also estimated. Heterogeneity was explored by random-effects meta-regression. Twenty-seven studies reporting on 39 groups of patients (N = 5874) were identified with 35 groups allowing for indirect and 8 for direct estimation of LSPR. The majority (~58%) of patients were HIV/HCV-coinfected. The estimated time-to-cirrhosis based on TE vs biopsy was 39 and 38 years, respectively. In univariate meta-regressions, male sex and HIV were positively and age at assessment, negatively associated with LSPRs. Noninvasive prognosis of HCV is consistent with FPRs in predicting time-to-cirrhosis, but more longitudinal studies of liver stiffness are needed to obtain refined estimates.

Future complications of chronic hepatitis C in a low-risk area: projections from the hepatitis c study in Northern Norway

BACKGROUND

Hepatitis C (HCV) infection causes an asymptomatic chronic hepatitis in most affected individuals, which often remains undetected until cirrhosis and cirrhosis-related complications occur. Screening of high-risk subjects in Northern Norway has revealed a relatively low prevalence in the general population (0.24%). Despite this, late complications of HCV infection are increasing. Our object was to estimate the future prevalence and complications of chronic HCV infection in the period 2013-2050 in a low-risk area.

METHODS

We have entered available data into a prognostic Markov model to project future complications to HCV infection.

RESULTS

The model extrapolates the prevalence in the present cohort of HCV-infected individuals, and assumes a stable low incidence in the projection period. We predict an almost three-fold increase in the incidence of cirrhosis (68 per 100,000), of decompensated cirrhosis (21 per 100,000) and of hepatocellular carcinoma (4 per 100,000) by 2050, as well as a six-fold increase in the cumulated number of deaths from HCV-related liver disease (170 per 100,000 inhabitants). All estimates are made assuming an unchanged treatment coverage of approximately 15%. The estimated numbers can be reduced by approximately 50% for cirrhosis, and by approximately one third for the other endpoints if treatment coverage is raised to 50%.

CONCLUSION

These projections from a low-prevalence area indicate a substantial rise in HCV-related morbidity and mortality in the coming years. The global HCV epidemic is of great concern and increased treatment coverage is necessary to reduce the burden of the disease.

A significant effect of the killer cell immunoglobulin-like receptor ligand human leucocyte antigen-C on fibrosis progression in chronic C hepatitis with or without liver transplantation

BACKGROUND & AIMS

The interaction of killer cell immunoglobulin-like receptors with their human leucocyte antigen ligands drives the activation and inhibition of natural killer cells. Natural killer cells could be implicated in the development of liver fibrosis in chronic hepatitis C.

METHODS

We analysed 206 non-transplanted and 53 liver transplanted patients, selected according to their Metavir fibrosis stage. Several variables such as the number of activator killer cell immunoglobulin-like receptors or the human leucocyte antigen ligands were considered in multinomial and logistic regression models. Possible confounding variables were also investigated.

RESULTS

The killer cell immunoglobulin-like receptors were not significant predictors of the fibrosis stage. Conversely, a significant reduction of the human leucocyte antigen-C1C2 genotype was observed in the most advanced fibrosis stage group (F4) in both cohorts. Furthermore, the progression rate of fibrosis was almost 10 times faster in the subgroup of patients after liver transplantation, and human leucocyte antigen-C1C2 was significantly reduced in this cohort compared with non-transplanted patients.

CONCLUSION

This study suggests a possible role of killer cell immunoglobulin-like receptors and their ligands in the development of liver damage. The absence of C1 and C2 ligands heterozygosity could lead to less inhibition of natural killer cells and a quicker progression to a high level of fibrosis in patients infected with hepatitis C virus, especially following liver transplantation.

Clinical outcomes of chronic hepatitis C patients related to baseline liver fibrosis stage: a hospital-based linkage study

BACKGROUND AND AIMS

Rates of long-term clinical outcomes of chronic hepatitis C in patients with none, mild or severe liver fibrosis are required to determine benefits of anti-viral therapies. This study evaluated long-term outcomes for chronic hepatitis C stratified by all Metavir fibrosis stages.

METHODS

Clinical outcomes were determined using population-based data linkage methodology for 880 hepatitis C patients who had a liver biopsy performed from 1992 to 2012.

RESULTS

During 9386 person-years of follow up, 28 patients developed hepatocellular carcinoma, 58 developed liver decompensation and 122 died or underwent liver transplantation. There was no significant difference in liver-related death for those with F0-F2 with an 18-year survival probability >94%. Hazard ratio of liver-related death for F3 compared with F0-F2 was 4.24 (P = 0.003), with no significant difference in the first 13-year follow up. The 15-year decompensation-free survival for F0, F1 and F2 was 100%, 96% and 94% respectively and for hepatocellular carcinoma-free survival was 100%, 99% and 98%. Hazard ratio of liver complication (hepatocellular carcinoma or decompensation)-free survival for F3 compared with F0-F2 was 3.22 (P = 0.001), with no significant difference during the first 7-year follow up. F4 had significantly higher risk of liver-related death, decompensation and hepatocellular carcinoma than F3 (P < 0.001).

CONCLUSIONS

Chronic hepatitis C patients with F2 or less had few liver complications after 15 years. For F3 patients, the significant increase in liver-related death occurred after 13 years and for liver complications after 7 years.

Hepatitis C virus (HCV) disease progression in people who inject drugs (PWID): A systematic review and meta-analysis

BACKGROUND

Understanding HCV disease progression rates among people who inject drugs (PWID) is important to setting policy to expand access to detection, diagnosis and treatment, and in forecasting the burden of disease. In this paper we synthesize existing data on the natural history of HCV among PWID, including fibrosis progression rates (FPR) and the incidence of compensated cirrhosis (CC), decompensated cirrhosis (DC), and hepatocellular carcinoma (HCC).

METHODS

We conducted electronic and manual searches for published and unpublished literature. Reports were eligible if they (i) included participants who were chronically infected with HCV and reported current or previous injection drug use; (ii) presented original data on disease progression in a study sample comprised of at least 90% PWID; (iii) published between January 1, 1990, and December 31, 2013; and (iv) included data from upper-middle- or high-income countries. Quality ratings were assigned using an adaptation of the Quality In Prognosis Studies (QUIPS) tool. We estimated pooled FPRs using the stage-constant and stage-specific methods, and pooled incidence rates of CC, DC, and HCC.

RESULTS

Twenty-one reports met the study inclusion criteria. Based on random-effect models, the pooled stage-constant FPR was 0.117 METAVIR units per year (95% CI, 0.099-0.135), and the stage-specific FPRs were F0→F1, 0.128 (95% CI 0.080, 0.176); F1→F2, 0.059 (95% CI 0.035, 0.082); F2→F3, 0.078 (95% CI 0.056, 0.100); and F3→F4, 0.116 (95% CI 0.070, 0.161). The pooled incidence rates of CC, DC, and HCC were 6.6 (95% CI 4.8, 8.4), 1.1 (95% CI 0.8, 1.4), and 0.3 (95% CI -0.1, 0.6) events per 1000 person-years, respectively. Following the stage-constant estimate, average time to cirrhosis is 34 years post-infection, and time to METAVIR stage F3 is 26 years; using the stage-specific estimates, time to cirrhosis is 46 years and time to F3 is 38 years.

CONCLUSION

Left untreated, PWID with chronic HCV infection will develop liver sequelae (including HCC) in mid- to late-adulthood. Delaying treatment with the new drug regimens until advanced fibrosis develops prolongs the period of infectiousness to perhaps thirty years. Scaling up of effective HCV prevention and early engagement in care and treatment will facilitate the elimination HCV as a source of serious disease in PWID.

Hepatitis C Virus Disease Progression in People Who Inject Drugs: Protocol for a Systematic Review and Meta-Analysis

Background

Most hepatitis C virus (HCV) infections in the United States occur following non-sterile injection drug use. However, the majority of people who inject drugs (PWID) with chronic HCV are not currently receiving care.

Objective

This paper presents our protocol for the systematic review and meta-analysis of data on the natural history of HCV among PWID and will inform modeling of the impact and cost-effectiveness of HCV management among this population. This study is conducted as part of the HCV Synthesis Project, which is funded to develop recommendations for HCV control strategies in the United States.

Methods

This protocol describes the methods used for a systematic review and meta-analysis of published and unpublished data on the natural history of HCV among PWID including viral clearance, fibrosis progression, and the incidence of compensated cirrhosis (CC), decompensated cirrhosis (DC), hepatocellular carcinoma (HCC), and liver-related mortality.

Results

Final results are anticipated by December 2016.

Conclusions

Methods used for the synthesis of data on disease progression among HCV mono-infected PWID are presented. Data from the systematic review and meta-analysis will be used to inform simulations of the natural history of HCV and to model the effects of prevention and treatment strategies to reduce disease burden and the associated costs to society and individual patients.

Cost-effectiveness of hepatitis C treatment for patients in early stages of liver disease

New treatments for hepatitis C virus (HCV) may be highly effective but are associated with substantial costs that may compel clinicians and patients to consider delaying treatment. This study investigated the cost-effectiveness of these treatments with a focus on patients in early stages of liver disease. We developed a state-transition (or Markov) model to calculate costs incurred and quality-adjusted life-years (QALYs) gained following HCV treatment, and we computed incremental cost-effectiveness ratios (cost per QALY gained, in 2012 US dollars) for treatment at different stages of liver disease versus delaying treatment until the subsequent liver disease stage. Our analysis did not include the potential treatment benefits associated with reduced non-liver-related mortality or preventing HCV transmission. All parameter values, particularly treatment cost, were varied in sensitivity analyses. The base case scenario represented a 55-year-old patient with genotype 1 HCV infection with a treatment cost of $100,000 and treatment effectiveness of 90%. In this scenario, for a 55-year-old patient with moderate liver fibrosis (Metavir stage F2), the cost-effectiveness of immediately initiating treatment at F2 (versus delaying treatment until F3) was $37,300/QALY. For patients immediately treated at F0 (versus delaying treatment until F1), the threshold of treatment costs that yielded $50,000/QALY and $100,000/QALY cost-effectiveness ratios were $22,200 and $42,400, respectively.

CONCLUSION

Immediate treatment of HCV-infected patients with moderate and advanced fibrosis appears to be cost-effective, and immediate treatment of patients with minimal or no fibrosis can be cost-effective as well, particularly when lower treatment costs are assumed.

Interferon-λ rs12979860 genotype and liver fibrosis in viral and non-viral chronic liver disease

Tissue fibrosis is a core pathologic process that contributes to mortality in ~45% of the population and is likely to be influenced by the host genetic architecture. Here we demonstrate, using liver disease as a model, that a single-nucleotide polymorphism (rs12979860) in the intronic region of interferon-λ4 (IFNL4) is a strong predictor of fibrosis in an aetiology-independent manner. In a cohort of 4,172 patients, including 3,129 with chronic hepatitis C (CHC), 555 with chronic hepatitis B (CHB) and 488 with non-alcoholic fatty liver disease (NAFLD), those with rs12979860CC have greater hepatic inflammation and fibrosis. In CHC, those with rs12979860CC also have greater stage-constant and stage-specific fibrosis progression rates (P<0.0001 for all). The impact of rs12979860 genotypes on fibrosis is maximal in young females, especially those with HCV genotype 3. These findings establish rs12979860 genotype as a strong aetiology-independent predictor of tissue inflammation and fibrosis.

Tissue fibrosis is a major contributor to mortality in the developed world. Here, the authors identify a genetic variant in the intronic region of interferon-λ4 that is a strong predictor of hepatic inflammation and fibrosis, independent of liver disease aetiology

Plasma Pro-C3 (N-terminal type III collagen propeptide) predicts fibrosis progression in patients with chronic hepatitis C

BACKGROUND & AIMS

Fibrogenesis results in release of certain extracellular matrix protein fragments into the circulation. We evaluated the diagnostic and prognostic performance of two novel serological markers, the precisely cleaved N-terminal propeptide of type III collagen (Pro-C3) and a peptide of helical collagen type III degradation (C3M), in chronic hepatitis C (CHC) patients.

METHOD

Pro-C3 and C3M were measured by ELISA in plasma from CHC patients (n = 194) from a prior phase II antifibrotic trial (NCT00244751). Plasma samples and paired liver biopsies were obtained at baseline and after 1-year. Patients were stratified according to Ishak stages 2-4. Internal cross-validation was performed by bootstrap analysis.

RESULTS

Pro-C3 levels were significantly higher in CHC patients in Ishak stage 4 compared to stage 2 (P < 0.001) or 3 (P < 0.01). Pro-C3 could significantly distinguish moderate (stage 4) from mild fibrosis (stage 2/3) (AUC = 0.72, P < 0.001). Importantly, an overall significance in Pro-C3 (P = 0.007) levels was observed between the groups of -1, 0, +1 and +2 change in Ishak stage at 12 months. Pro-C3 was significantly increased in group +1 (P = 0.030) and +2 (P = 0.021) compared to group 0. No significant differences were observed for C3M. In multivariate analysis, only baseline Pro-C3, but not FibroTest, had an independent association with fibrosis progression.

CONCLUSIONS

Pro-C3 is a useful test to predict fibrogenesis and monitor disease progression. Moreover, it could differentiate mild from moderate disease. Pro-C3 may become a promising blood parameter be included in future studies for monitoring disease progression and eventually for evaluation of potential antifibrotic therapies.

Natural history of hepatitis C

There has long been evidence that hepatitis C can lead to persistent infection in a high proportion of infected individuals, and can progress to chronic liver disease, cirrhosis and hepatocellular carcinoma (HCC). The transition from acute to chronic hepatitis C is usually sub-clinical. Accurate studies of the time course for clearance of acute hepatitis C are difficult to carry out because of the silent onset of the acute disease. The likelihood of spontaneous HCV resolution is associated with several genetic factors, including IL28B inheritance and the DQB1*0301 allele of the major histocompatibility complex class II. Most data suggest that resolution in the acute phase without progression to chronic disease is not accompanied by significant disease, but minor histological lesions have been observed in anti-HCV positive, HCV RNA negative individuals. The risk of reinfection remains a possibility after clearance of acute hepatitis C. High rates of sexually-transmitted infection are being reported in HIV positive men who have sex with men (MSM). Chronic infection with HCV is the leading cause of end-stage liver disease, hepatocellular carcinoma (HCC) and liver related death in the Western world. The natural history of the chronic disease remains incompletely defined. It is generally a slowly progressive disease characterized by persistent hepatic inflammation, leading to the development of cirrhosis in approximately 10-20% of patients over 20-30 years of HCV infection. However, the published data indicate varying progression rates to cirrhosis. Overall, once cirrhosis has developed there is a 1-5% annual risk of HCC and a 3-6% annual risk of hepatic decompensation. Following an episode of decompensation the risk of death in the following year is between 15% and 20%. The high number of chronically infected individuals, the burden of disease, and the absence of a vaccine indicates that treatment will form part of the disease control but the impact, effectiveness and outcomes of treatment in various groups remain uncertain. Several studies and meta-analysis have concluded that eradication of HCV with antiviral therapy reduces the risk of HCC in patients with chronic hepatitis C, independent of fibrosis stage, but the risk is not eliminated.

Cost effectiveness of hepatitis C-related interventions targeting substance users and other high-risk groups: a systematic review

BACKGROUND AND OBJECTIVE

In developed countries, injection drug users have the highest prevalence and incidence of hepatitis C virus (HCV) infection. Clinicians and policy makers have several options for reducing morbidity and mortality related to HCV infection, including preventing new infections, screening high-risk populations, and optimizing uptake and delivery of antiviral therapy. Cost-effectiveness analyses provide an estimate of the value for money associated with adopting healthcare interventions. Our objective was to determine the cost effectiveness of hepatitis C interventions (prevention, screening, treatment) targeting substance users and other groups with a high proportion of substance users.

METHODS

We conducted a systematic search of MEDLINE, EMBASE, CINAHL, HealthSTAR and EconLit, and the grey literature. Studies were critically appraised using the Drummond and Jefferson, Neumann et al. and Philips et al. checklists. We developed and applied a quality appraisal instrument specific to cost-effectiveness analyses of HCV interventions. In addition, we summarized cost-effectiveness estimates using a single currency and year ($US, year 2009 values).

RESULTS

Twenty-one economic evaluations were included, which addressed prevention (three), screening (ten) and treatment (eight). The quality of the analyses varied greatly. A significant proportion did not incorporate important aspects of HCV natural history, disease costs and antiviral therapy. Incremental cost-effectiveness ratios (ICERs) ranged from dominant (less costly and more effective) to $US603,352 per QALY. However, many ICERs were less than $US100,000 per QALY. Screening and treatment interventions involving pegylated interferon and ribavirin were generally cost effective at the $US100,000 per QALY threshold, with the exception of some subgroups, such as immune compromised patients with genotype 1 infections.

CONCLUSIONS

No clear consensus emerged from the studies demonstrating that prevention, screening or treatment provides better value for money as each approach can be economically attractive in certain subgroups. More high-quality economic evaluations of preventing, identifying and treating HCV infection in substance users are needed.

Genome-wide association study identifies variants associated with progression of liver fibrosis from HCV infection

BACKGROUND & AIMS

Polymorphisms in IL28B were shown to affect clearance of hepatitis C virus (HCV) infection in genome-wide association (GWA) studies. Only a fraction of patients with chronic HCV infection develop liver fibrosis, a process that might also be affected by genetic factors. We performed a 2-stage GWA study of liver fibrosis progression related to HCV infection.

METHODS

We studied well-characterized HCV-infected patients of European descent who underwent liver biopsies before treatment. We defined various liver fibrosis phenotypes on the basis of METAVIR scores, with and without taking the duration of HCV infection into account. Our GWA analyses were conducted on a filtered primary cohort of 1161 patients using 780,650 single nucleotide polymorphisms (SNPs). We genotyped 96 SNPs with P values <5 × 10(-5) from an independent replication cohort of 962 patients. We then assessed the most interesting replicated SNPs using DNA samples collected from 219 patients who participated in separate GWA studies of HCV clearance.

RESULTS

In the combined cohort of 2342 HCV-infected patients, the SNPs rs16851720 (in the total sample) and rs4374383 (in patients who received blood transfusions) were associated with fibrosis progression (P(combined) = 8.9 × 10(-9) and 1.1 × 10(-9), respectively). The SNP rs16851720 is located within RNF7, which encodes an antioxidant that protects against apoptosis. The SNP rs4374383, together with another replicated SNP, rs9380516 (P(combined) = 5.4 × 10(-7)), were linked to the functionally related genes MERTK and TULP1, which encode factors involved in phagocytosis of apoptotic cells by macrophages.

CONCLUSIONS

Our GWA study identified several susceptibility loci for HCV-induced liver fibrosis; these were linked to genes that regulate apoptosis. Apoptotic control might therefore be involved in liver fibrosis.

The natural history of hepatitis C infection acquired through injection drug use: meta-analysis and meta-regression

BACKGROUND & AIMS

Our aim was to estimate the rate of progression to cirrhosis for those infected with hepatitis C virus (HCV) through injection drug use.

METHODS

We searched the published literature for articles assessing cirrhosis in this population and abstracted data on cirrhosis prevalence, mean duration of infection, mean age, mean alanine aminotransferase (ALT) enzyme levels, proportion of males, proportion HIV co-infected, proportion consuming excessive alcohol, and study setting. Summary progression rates were estimated using weighted averages and random effects Poisson meta-regression. The impact of co-variates was assessed by estimating the posterior probability that the relative risk (RR) of progression exceeded 1.0.

RESULTS

A total of 47 published articles were identified. After adjusting for covariates in 44 studies representing 6457 patients, the estimated rate of progression to cirrhosis, was 8.1 per 1000 person-years (95% credible region (CR), 3.9-14.7). This corresponds to a 20-year cirrhosis prevalence of 14.8% (95% CR, 7.5-25.5). A 5% increase in the proportion of male participants and a 5% increase in the proportion consuming excessive alcohol were associated with faster progression (probability RR>1=0.97 and 0.92, respectively). A 5% increase in the proportion of HIV co-infected, an increase in ALT of 5 IU/L and studies in settings with a high risk of referral bias were not associated with faster progression (probability RR>1=0.42, 0.65, and 0.43, respectively).

CONCLUSIONS

Analysis of aggregate level data suggests that for patients who contracted HCV through injection drug use prognosis is poor in populations with many male patients and high levels of alcohol consumption.

Aging of hepatitis C virus (HCV)-infected persons in the United States: a multiple cohort model of HCV prevalence and disease progression

BACKGROUND & AIMS

The prevalence of chronic hepatitis C (CH-C) remains high and the complications of infection are common. Our goal was to project the future prevalence of CH-C and its complications.

METHODS

We developed a multicohort natural history model to overcome limitations of previous models for predicting disease outcomes and benefits of therapy.

RESULTS

Prevalence of CH-C peaked in 2001 at 3.6 million. Fibrosis progression was inversely related to age at infection, so cirrhosis and its complications were most common after the age of 60 years, regardless of when infection occurred. The proportion of CH-C with cirrhosis is projected to reach 25% in 2010 and 45% in 2030, although the total number with cirrhosis will peak at 1.0 million (30.5% higher than the current level) in 2020 and then decline. Hepatic decompensation and liver cancer will continue to increase for another 10 to 13 years. Treatment of all infected patients in 2010 could reduce risk of cirrhosis, decompensation, cancer, and liver-related deaths by 16%, 42%, 31%, and 36% by 2020, given current response rates to antiviral therapy.

CONCLUSIONS

Prevalence of hepatitis C cirrhosis and its complications will continue to increase through the next decade and will mostly affect those older than 60 years of age. Current treatment patterns will have little effect on these complications, but wider application of antiviral treatment and better responses with new agents could significantly reduce the impact of this disease in coming years.

Genotype 3 is associated with accelerated fibrosis progression in chronic hepatitis C

BACKGROUND/AIMS

While several risk factors for the histological progression of chronic hepatitis C have been identified, the contribution of HCV genotypes to liver fibrosis evolution remains controversial. The aim of this study was to assess independent predictors for fibrosis progression.

METHODS

We identified 1189 patients from the Swiss Hepatitis C Cohort database with at least one biopsy prior to antiviral treatment and assessable date of infection. Stage-constant fibrosis progression rate was assessed using the ratio of fibrosis Metavir score to duration of infection. Stage-specific fibrosis progression rates were obtained using a Markov model. Risk factors were assessed by univariate and multivariate regression models.

RESULTS

Independent risk factors for accelerated stage-constant fibrosis progression (>0.083 fibrosis units/year) included male sex (OR=1.60, [95% CI 1.21-2.12], P<0.001), age at infection (OR=1.08, [1.06-1.09], P<0.001), histological activity (OR=2.03, [1.54-2.68], P<0.001) and genotype 3 (OR=1.89, [1.37-2.61], P<0.001). Slower progression rates were observed in patients infected by blood transfusion (P=0.02) and invasive procedures or needle stick (P=0.03), compared to those infected by intravenous drug use. Maximum likelihood estimates (95% CI) of stage-specific progression rates (fibrosis units/year) for genotype 3 versus the other genotypes were: F0-->F1: 0.126 (0.106-0.145) versus 0.091 (0.083-0.100), F1-->F2: 0.099 (0.080-0.117) versus 0.065 (0.058-0.073), F2-->F3: 0.077 (0.058-0.096) versus 0.068 (0.057-0.080) and F3-->F4: 0.171 (0.106-0.236) versus 0.112 (0.083-0.142, overall P<0.001).

CONCLUSIONS

This study shows a significant association of genotype 3 with accelerated fibrosis using both stage-constant and stage-specific estimates of fibrosis progression rates. This observation may have important consequences for the management of patients infected with this genotype.

Bias in Markov models of disease

We examine bias in Markov models of diseases, including both chronic and infectious diseases. We consider two common types of Markov disease models: ones where disease progression changes by severity of disease, and ones where progression of disease changes in time or by age. We find sufficient conditions for bias to exist in models with aggregated transition probabilities when compared to models with state/time dependent transition probabilities. We also find that when aggregating data to compute transition probabilities, bias increases with the degree of data aggregation. We illustrate by examining bias in Markov models of Hepatitis C, Alzheimer's disease, and lung cancer using medical data and find that the bias is significant depending on the method used to aggregate the data. A key implication is that by not incorporating state/time dependent transition probabilities, studies that use Markov models of diseases may be significantly overestimating or underestimating disease progression. This could potentially result in incorrect recommendations from cost-effectiveness studies and incorrect disease burden forecasts.

Re-weighted inference about hepatitis C virus-infected communities when analysing diagnosed patients referred to liver clinics

To project national hepatitis C virus (HCV) burden, unbiased estimation of HCV progression to liver cirrhosis is required for the whole community of HCV-infected individuals. However, widely varying estimates of progression rates to cirrhosis have been produced. This disparity is partly associated with the statistical methods applied, but is mainly due to the differing types of study cohort. We use an inverse probability weighted estimation method to recover the true parameters for the (Weibull regression) model that determines the incubation period from infection to cirrhosis for the community of HCV-infected individuals, when there is cirrhosis-related recruitment bias to the studied cohort. We apply the method to simulated data for a liver clinic which attracts patients from a community of 1000 HCV-infected individuals under different event-biased referral patterns. We investigate how well the method performs in recovering the true community parameters, and then apply it to Edinburgh Royal Infirmary's liver clinic series. The results obtained are compared to those from a Weibull survival analysis which ignores the selection bias.

Natural history of hepatitis C virus infection in HIV-infected individuals and the impact of HIV in the era of highly active antiretroviral therapy: a meta-analysis

OBJECTIVES

To estimate stage-specific transition probabilities in individuals coinfected with HIV and hepatitis C virus (HCV), to examine the effect of covariates on these rates, and to investigate the effect of HIV on HCV-related cirrhosis in the era of highly active antiretroviral therapy (HAART).

DESIGN

Systematic review of natural history studies among HCV-infected individuals.

METHODS

Markov maximum likelihood estimation method was used to estimate stage-specific transition probabilities. A meta-analysis was performed to obtain pooled transition probabilities, and a meta-regression to investigate the impact of covariates on these rates. Risk of cirrhosis between individuals monoinfected with HCV and coinfected with HIV/HCV were compared by HAART status.

RESULTS

The estimated mean (95% confidence intervals) annual transition probabilities of 3567 individuals coinfected with HIV/HCV (n = 17 studies) were as follows: fibrosis stage (F) F0 --> F1 0.122 (0.098-0.153); F1 --> F2 0.115 (0.095-0.140); F2 --> F3 0.124 (0.097-0.159); and F3 --> F4 0.115 (0.098-0.135) units/year. The prevalence of cirrhosis after 20 and 30 years of HCV infection was 21% (16-28%) and 49% (40-59%), respectively. Longer duration of HCV infection was significantly associated with slower rate of fibrosis progression. The overall rate ratio of cirrhosis between individuals coinfected with HIV/HCV and monoinfected with HCV (n = 27 studies) was 2.1 (1.5-3.0), 2.5 (1.8-3.4) in the non-HAART group, and 1.7 (1.1-2.8) in the HAART group.

CONCLUSION

The rate of fibrosis progression among individuals coinfected with HIV/HCV appears constant. Our results confirm that chronic hepatitis C outcomes are worse among coinfected individuals. Over the period studied, HAART did not appear to fully correct the adverse effect of HIV infection on HCV prognosis.

Estimation of stage-specific fibrosis progression rates in chronic hepatitis C virus infection: a meta-analysis and meta-regression

Published estimates of liver fibrosis progression in individuals with chronic hepatitis C virus (HCV) infection are heterogeneous. We aimed to estimate stage-specific fibrosis progression rates and their determinants in these individuals. A systematic review of published prognostic studies was undertaken. Study inclusion criteria were as follows: (1) presence of HCV infection determined by serological assays; (2) available information about age at assessment of liver disease or HCV acquisition; (3) duration of HCV infection; and (4) histological and/or clinical diagnosis of cirrhosis. Annual stage-specific transition probabilities (F0-->F1, ... , F3-->F4) were derived using the Markov maximum likelihood estimation method and a meta-analysis was performed. The impact of potential covariates was evaluated using meta-regression. A total of 111 studies of individuals with chronic HCV infection (n = 33,121) were included. Based on the random effects model, the estimated annual mean (95% confidence interval) stage-specific transition probabilities were: F0-->F1 0.117 (0.104-0.130); F1-->F2 0.085 (0.075-0.096); F2-->F3 0.120 (0.109-0.133); and F3-->F4 0.116 (0.104-0.129). The estimated prevalence of cirrhosis at 20 years after the infection was 16% (14%-19%) for all studies, 18% (15%-21%) for cross-sectional/retrospective studies, 7% (4%-14%) for retrospective-prospective studies, 18% (16%-21%) for studies conducted in clinical settings, and 7% (4%-12%) for studies conducted in nonclinical settings. Duration of infection was the most consistent factor significantly associated with progression of fibrosis.

CONCLUSION

Our large systematic review provides increased precision in estimating fibrosis progression in chronic HCV infection and supports nonlinear disease progression. Estimates of progression to cirrhosis from studies conducted in clinical settings were lower than previous estimates.

The changing epidemiology and natural history of hepatitis C virus infection

Injection drug use remains the predominant mode of transmission of hepatitis C virus (HCV) infection. Growing numbers of persons who have been chronically infected with HCV for 20 or more years are coming to medical attention and are at risk for serious complications of chronic infection, including cirrhosis and hepatocellular carcinoma. Factors linked with the development of advanced fibrosis and cirrhosis include age at infection, duration of infection, heavy alcohol use, coinfections with HIV or hepatitis B virus, and male sex. Emerging risk factors for disease progression include steatosis, insulin resistance (and factors associated with the metabolic syndrome), and host genetics.

Antiretroviral Therapy Based on Protease Inhibitors as a Protective Factor against Liver Fibrosis Progression in Patients with Chronic Hepatitis C

Cohort studies have shown that highly active antiretroviral therapy (HAART) can improve liver-related mortality in HIV/hepatitis C virus (HCV)-coinfected patients. A reduction in the accelerated liver fibrosis progression observed in HIV infection induced by HAART could explain these findings. A few studies have assessed the impact of HAART on liver fibrosis, but with contradictory results. Therefore, we evaluated the associations between the use of different antiretroviral drug classes and HAART combinations, and liver fibrosis in HIV-infected patients with chronic hepatitis C. Six hundred and eighty-three HIV/HCV-coinfected patients, who underwent a liver biopsy and who had not received anti-HCV treatment were included. Age at HCV infection <23 years (adjusted odds ratio [AOR]=0.7, 95% confidence interval [95% CI]=0.3-0.9, P=0.05) and protease inhibitor (PI)-based HAART versus no use of HAART (AOR=0.5, 95% CI=0.3-0.9, P=0.01) were negatively associated with advanced fibrosis (≥F3). PI-based HAART versus no use of HAART (AOR=0.4, 95% CI=0.2-0.7, P=0.001) was negatively associated with fibrosis progression rate ≥0.2 units/year and independently of age at HCV infection and CD4+ T-cell counts. Fifteen (17%) patients treated only with PIs and zidovudine plus lamivudine showed ≥F3, compared with 65 (37%) patients without HAART ( P=0.001). Forty (31%) patients on PI and stavudine plus lamivudine showed ≥F3 ( P=0.3, when compared with patients with no HAART). The use of PI-based HAART in HIV/HCV-coinfected patients is associated with less severe fibrosis and slower progression of fibrosis. The nucleoside analogue backbone in a HAART regimen may influence this association.

Estimated progression rates in three United Kingdom hepatitis C cohorts differed according to method of recruitment

OBJECTIVES

To estimate hepatitis C virus (HCV) progression rates between disease stages prior to cirrhosis, using data from liver biopsies in three observational cohorts. To demonstrate how the method of cohort recruitment can influence the estimation of HCV-progression rates.

STUDY DESIGN AND SETTING

Data came from three United Kingdom observational cohorts, assembled from different referral sources. In total, 987 HCV-infected patients with an estimated (or known) date of infection and at least one histologically scored liver biopsy were eligible for inclusion in the analysis. Liver biopsy scores were used to determine the stage of HCV-related liver disease. A three-state continuous time Markov model was used to estimate covariate-specific average probabilities of progression of disease.

RESULTS

After adjusting for confounders, considerably different rates of disease progression were estimated in the three cohorts. For a group of patients with the same demographics, the estimated 20-year probability of progression to cirrhosis was 12% (95% confidence interval CI = 6-22) in a hospital-based cohort, 6% (95% CI = 3-13) in a posttransfusion cohort, and 23% (95% CI = 14-37) in a cohort recruited from a tertiary referral center.

CONCLUSION

Researchers using estimates of disease progression should be aware that the method of cohort recruitment has considerable influence on the progression rates that are derived.

Natural history of hepatitis C

Fifteen years after the discovery of the hepatitis C virus, a substantial amount of information has been learned about the natural history of infection. Testing for viral nucleic acid made it possible to accurately diagnose chronic infection and provided a more precise estimate of the overall frequency of viral persistence. Although cirrhosis and hepatocellular carcinoma can arise in persons with chronic hepatitis C, these outcomes do not always occur. The cirrhosis risk is greater in those who are infected at older ages, those who drink >50 g of alcohol each day, and persons coinfected with HIV. However, much of the person-to-person variability in progression of chronic hepatitis C remains unexplained. The ability to detect persons at highest risk of progression remains incomplete and represents an important future challenge in the understanding of the natural history of hepatitis C.