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

Anti-Hepatitis C (HCV) test positivity and new HCV diagnoses among women tested in antenatal services in England between 2015-2019

OBJECTIVE

To determine associations with hepatitis C virus (HCV) positivity, new HCV diagnoses and subsequent linkage to HCV treatment services among pregnant women in England.

METHOD

A retrospective cohort using routine laboratory tests for HCV-specific antibody (anti-HCV) and HCV-RNA undertaken during antenatal attendances England. All women receiving at least one anti-HCV test during an antenatal clinic attendance between 2015 and 2019 were included. Multivariable logistic regression was used to investigate sociodemographic associations with anti-HCV test positivity among pregnant women who did (PWIDs) and did not (non-PWIDs) inject drugs, as well as to identify sociodemographic factors associated with being newly diagnosed during pregnancy. Linkage to antiviral treatment services and treatment outcomes were determined for those women who tested HCV-RNA positive.

RESULTS

32,088 women (median age 32 years, 19,664 (61 %) UK-born, 337 (1.1 %) PWID) received an anti-HCV test among whom 814 (2.5 %) had a positive anti-HCV test (95 % confidence interval [2.4-2.7 %]). Anti-HCV test positivity was 2.1 % [2.0-2.3 %] among non-PWIDs and 40 % [35-46 %] among PWIDs. In multivariable analyses among non-PWIDs, anti-HCV test positivity was associated with older age, living in more deprived areas, and varied by ethnicity and country of birth. Among PWIDs, anti-HCV test positivity was associated with older age only. Three hundred and twenty (39 %) of the women testing anti-HCV positive were new diagnoses; those who were newly diagnosed were younger and lived in less deprived than those with a prior diagnosis whereas PWIDs were less likely to be newly diagnosed. HCV-RNA positivity was 52 % (n = 330/640, 95 %CI[47.6-55.5 %]) among those with an HCV-RNA test within 30 days, and 75 % (n = 220/293, 95 %CI[69.7-79.9 %]) of those eligible for treatment had engaged in HCV treatment services after antenatal testing.

CONCLUSIONS

Antenatal testing for HCV provides an opportunity for new case findings and engagement with treatment services where needed. Therefore, universal opt-out testing for HCV antenatally should be reconsidered.

A rapid review of antenatal hepatitis C virus testing in the United Kingdom

BACKGROUND

The United Kingdom (UK) has committed to the World Health Organization's viral hepatitis elimination targets. New case finding strategies, such as antenatal testing, may be needed to achieve these targets. We conducted a rapid review to understand hepatitis C-specific antibody (anti-HCV) and HCV RNA test positivity in antenatal settings in the United Kingdom to inform guidance.

METHODS

Articles and conference abstracts published between January 2000 and June 2022 reporting anti-HCV testing in antenatal settings were identified through PubMed and Web of Science searches. Results were synthesised using a narrative approach.

RESULTS

The search identified 2,011 publications; 10 studies were included in the final synthesis. Seven studies used anonymous testing methods and three studies used universal opt-out testing. Anti-HCV test positivity ranged from 0.1 to 0.99%, with a median value of 0.38%. Five studies reported HCV RNA positivity, which ranged from 0.1 to 0.57% of the testing population, with a median value of 0.22%. One study reported cost effectiveness of HCV and found it to be cost effective at £9,139 per quality adjusted life years.

CONCLUSION

The relative contribution of universal opt-out antenatal testing for HCV should be reconsidered, as antenatal testing could play an important role in new case-finding and aid achieving elimination targets.

Investigating rates and risk factors for hepatitis C virus reinfection in people receiving antiviral treatment in England

England has committed to the World Health Organization target to eliminate hepatitis C virus (HCV) as a public threat by the year 2030. Given successful treatments for HCV in recent years, it is unclear whether HCV reinfection will impact England's ability to achieve HCV elimination. We aimed to estimate the HCV reinfection rate among a cohort of patients receiving antiviral treatment using available surveillance data. Linkage between a treatment dataset from 2015 to 2019 and an HCV RNA testing dataset were used to identify people who experienced reinfection using three criteria. A Cox proportional hazards model was used to determine risk factors associated with HCV reinfection among a cohort who received treatment and had follow-up HCV RNA testing. The reinfection rate among those receiving HCV treatment was 7.91 per 100 person-years (PYs, 95% confidence interval (CI) 7.37-8.49) and highest among current injecting drug users (22.55 per 100 PYs, 95% CI 19.98-25.46) and people who had been in prison (20.42 per 100 PYs, 95% CI 17.21-24.24). In the adjusted model, women had a significantly reduced risk of reinfection. Being of younger age, current injecting drug users, and receipt of first treatment in prison were each significantly associated with increased risk of reinfection. Two-fifths of those with reinfection (43%, n = 329/767) were linked to treatment after reinfection, and of those starting treatment, three quarters (75%, n = 222/296) achieved a sustained virologic response. Guidance for testing groups at risk of reinfection and harm reduction strategies to minimize transmission should be implemented if England is to achieve HCV elimination targets.

A mathematical model by route of transmission and fibrosis progression to estimate undiagnosed individuals with HCV in different Italian regions

BACKGROUND

Although an increase in hepatitis C virus (HCV) prevalence from Northern to Southern Italy has been reported, the burden of asymptomatic individuals in different Italian regions is currently unknown.

METHODS

A probabilistic approach, including a Markov chain for liver disease progression, was applied to estimate current HCV viraemic burden. The model defined prevalence by geographic area using an estimated annual historical HCV incidence by age, treatment rate, and migration rate from the Italian National database. Viraemic infection by age group was estimated for each region by main HCV transmission routes of individuals for stage F0-F3 (i.e. patients without liver cirrhosis and thus potentially asymptomatic) and F4 (patients with liver cirrhosis, thus potentially symptomatic).

RESULTS

By January 2020, it was estimated that there were 409,184 Italian individuals with HCV (prevalence of 0.68%; 95% CI: 0.54-0.82%), of which 300,171 (0.50%; 95% CI: 0.4-0.6%) were stage F0-F3. Considering all individuals with HCV in stage F0-F3, the geographical distributions (expressed as the proportion of HCV infected individuals by macroarea within the overall estimated number of F0-F3 individuals and prevalence values, expressed as the percentage of individuals with HCV versus the overall number of individuals for each macroarea) were as follows: North 42.1% (0.45%; 95% CI: 0.36-0.55%), Central 24.1% (0.61%; 95% CI: 0.48-0.74%), South 23.2% (0.50%; 95% CI: 0.4-0.61%), and the Isles 10.6% (0.49%; 95% CI: 0.39-0.59%). The population of people who inject drugs accounted for 50.4% of all individuals infected (F0-F3). Undiagnosed individuals (F0-F3) were ~ 15 years younger (⁓ 50 years) compared with patients with stage F4 (⁓ 65 years), with similar age distributions across macroareas. In contrast to what has been reported on HCV epidemiology in Italy, an increasing trend in the proportion of potentially undiagnosed individuals with HCV (absolute number within the F0-F3) from South (23.2%) to North (42.1%) emerged, independent of similar regional prevalence values.

CONCLUSION

This targeted approach, which addresses the specific profile of undiagnosed individuals, is helpful in planning effective elimination strategies by region in Italy and could be a useful methodology for other countries in implementing their elimination plans.

Estimated prevalence of undiagnosed HCV infected individuals in Italy: A mathematical model by route of transmission and fibrosis progression

BACKGROUND

The universal treatment of diagnosed patients with chronic HCV infection has been widely conducted in Italy since 2017. However, the pool of individuals diagnosed but yet to be treated in Italy has been estimated to end around 2025, leaving a significant proportion of infected individuals undiagnosed/without care. Estimates of this population are currently unknown.

METHODS

A probabilistic modelling approach was applied to estimate annual historical HCV incident cases by their age-group (0-100 years) distribution from available literature and Italian National database (1952 to October 2019). Viraemic infection rates were modelled on the main infection routes in Italy: people who inject drugs (PWID), tattoos, sexual transmission, glass syringe use, blood transfusion and vertical transmission. Annual liver fibrosis stage transition probabilities were modelled using a Markov model. The number of HCV viraemic asymptomatic (fibrosis stage F0-F3:potentially undiagnosed/unlinked to care) and symptomatic (fibrosis stage F4: potentially linked to care) individuals was estimated.

RESULTS

By October 2019, total viraemic HCV individuals in Italy (excluding treated patients since 1992) were estimated to be 410,775 (0.68 % of current population of Italy; 95 % CI: 0.64-0.71%, based on the current Italian population), of which 281,809 (0.47 %; 95 % CI:0.35-0.60%) were fibrosis stage F0-F3. Among different high risk groups in stage F0-F3, the following distribution was estimated: PWID; 52.0 % (95 % CI:37.9-66.6 %), tattoo; 28.8 % (95 % CI:23-32.3 %), sexual transmission; 12.0 % (95 % CI:9.6-13.7 %), glass syringe and transfusion; 6.4 % (95 % CI:2.4-17.8 %), and vertical transmission; 0.7 % (95 % CI:0.4-1.2 %).

CONCLUSION

Under the assumption that most untreated HCV-infected individuals with stage F0-F3 are undiagnosed, more than 280,000 individuals are undiagnosed and/or unlinked to care in Italy. Marked heterogeneity across the major routes of HCV transmission was estimated. This modelling approach may be a useful tool to characterise the HCV epidemic profile also in other countries, based on country specific epidemiology and HCV main transmission routes.

Cost-effectiveness of using hepatitis C viremic hearts for transplantation into HCV-negative recipients

Outcomes following hepatitis C virus (HCV)-viremic heart transplantation into HCV-negative recipients with HCV treatment are good. We assessed cost-effectiveness between cohorts of transplant recipients willing and unwilling to receive HCV-viremic hearts. Markov model simulated long-term outcomes among HCV-negative patients on the transplant waitlist. We compared costs (2018 USD) and health outcomes (quality-adjusted life-years, QALYs) between cohorts willing to accept any heart and those willing to accept only HCV-negative hearts. We assumed 4.9% HCV-viremic donor prevalence. Patients receiving HCV-viremic hearts were treated, assuming $39 600/treatment with 95% cure. Incremental cost-effectiveness ratios (ICERs) were compared to a $100 000/QALY gained willingness-to-pay threshold. Sensitivity analyses included stratification by blood type or region and potential negative consequences of receipt of HCV-viremic hearts. Compared to accepting only HCV-negative hearts, accepting any heart gained 0.14 life-years and 0.11 QALYs, while increasing costs by $9418/patient. Accepting any heart was cost effective (ICER $85 602/QALY gained). Results were robust to all transplant regions and blood types, except type AB. Accepting any heart remained cost effective provided posttransplant mortality and costs among those receiving HCV-viremic hearts were not >7% higher compared to HCV-negative hearts. Willingness to accept HCV-viremic hearts for transplantation into HCV-negative recipients is cost effective and improves clinical outcomes.

Multistate analysis from cross-sectional and auxiliary samples

Epidemiological studies routinely involve cross-sectional sampling of a population comprised of individuals progressing through life history processes. We consider features of a cross-sectional sample in terms of the intensity functions of a progressive multistate disease process under stationarity assumptions. The limiting values of estimators for regression coefficients in naive logistic regression models are studied, and simulations confirm the key asymptotic results that are relevant in finite samples. We also consider the need for and the use of data from auxiliary samples, which enable one to fit the full multistate life history process. We conclude with an application to data from a national cross-sectional sample assessing marker effects on psoriatic arthritis among individuals with psoriasis.

Multistate Markov Model to Predict the Prognosis of High-Risk Human Papillomavirus-Related Cervical Lesions

Cervical intraepithelial neoplasia (CIN) has a natural history of bidirectional transition between different states. Therefore, conventional statistical models assuming a unidirectional disease progression may oversimplify CIN fate. We applied a continuous-time multistate Markov model to predict this CIN fate by addressing the probability of transitions between multiple states according to the genotypes of high-risk human papillomavirus (HPV). This retrospective cohort comprised 6022 observations in 737 patients (195 normal, 259 CIN1, and 283 CIN2 patients at the time of entry in the cohort). Patients were followed up or treated at the University of Tokyo Hospital between 2008 and 2015. Our model captured the prevalence trend satisfactory, particularly for up to two years. The estimated probabilities for 2-year transition to CIN3 or more were the highest in HPV 16-positive patients (13%, 30%, and 42% from normal, CIN1, and CIN2, respectively) compared with those in the other genotype-positive patients (3.1%-9.6%, 7.6%-16%, and 21%-32% from normal, CIN1, and CIN2, respectively). Approximately 40% of HPV 52- or 58-related CINs remained at CIN1 and CIN2. The Markov model highlights the differences in transition and progression patterns between high-risk HPV-related CINs. HPV genotype-based management may be desirable for patients with cervical lesions.

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.

Cost-Effectiveness of One-Time Birth Cohort Screening for Hepatitis C as Part of the National Health Service Health Check Program in England

BACKGROUND AND OBJECTIVES

Birth cohort screening for the hepatitis C virus (HCV) has been implemented in the US, but there is little evidence of its cost-effectiveness in England. We aim to evaluate the cost-effectiveness of one-time HCV screening for individuals born between 1950 and 1979 as part of the National Health Service health check in England, a health check for adults aged 40 to 74 years in primary care.

METHODS

A Markov model was developed to analyze add-on HCV testing to the National Health Service health check for individuals in birth cohorts between 1950 and 1979, versus current background HCV testing only, over a lifetime horizon. The model used data from a back-calculation model of the burden of HCV in England, sentinel surveillance of HCV testing, and published literature. Results are presented from a health service perspective in pounds in 2017, as incremental cost-effectiveness ratios per quality-adjusted life years gained.

RESULTS

The base-case incremental cost-effectiveness ratios ranged from £7648 to £24 434, and £18 681 to £46 024, across birth cohorts when considering 2 sources of HCV transition probabilities. The intervention is most likely to be cost-effective for those born in the 1970s, and potentially cost-effective for those born from 1955 to 1969. The model results were most sensitive to the source of HCV transition probabilities, the probability of referral and receiving treatment, and the HCV prevalence among testers. The maximum value of future research across all birth cohorts was £11.3 million at £20 000 per quality-adjusted life years gained.

CONCLUSION

Birth cohort screening is likely to be cost-effective for younger birth cohorts, although considerable uncertainty exists for other birth cohorts. Further studies are warranted to reduce uncertainty in cost-effectiveness and consider the acceptability of the intervention.

Score tests based on a finite mixture model of Markov processes under intermittent observation

A mixture model is described, which accommodates different Markov processes governing disease progression in a finite set of latent classes. We give special attention to the setting in which individuals are examined intermittently and transition times are consequently interval censored. A score test is developed to identify genetic markers associated with class membership. Simulation studies are conducted to validate the algorithm, assess the finite sample properties of the estimators, and assess the frequency properties of the score tests. A permutation test is recommended for settings when there is concern that the asymptotic approximation to the score test is poor. An application involving progression in joint damage in psoriatic arthritis (PsA) provides illustration and identifies human leukocyte antigen markers associated with unilateral and bilateral sacroiliac damage in individuals with PsA.

Monitoring the hepatitis C epidemic in England and evaluating intervention scale-up using routinely collected data

In England, 160 000 individuals were estimated to be chronically infected with hepatitis C virus (HCV) in 2005 and the burden of severe HCV-related liver disease has increased steadily for the past 15 years. Direct-acting antiviral treatments can clear infection in most patients, motivating HCV elimination targets. However, the current burden of HCV is unknown and new methods are required to monitor progress. We employed a Bayesian back-calculation approach, combining data on severe HCV-related liver disease and disease progression, to reconstruct historical HCV incidence and estimate current prevalence in England. We explicitly modelled infections occurring in people who inject drugs, the key risk group, allowing information on the size of this population and surveillance data on HCV prevalence to inform recent incidence. We estimated that there were 143 000 chronic infections in 2015 (95% credible interval 123 000-161 000), with 34% and 54% in those with recent and past injecting drug use, respectively. Following the planned scale-up of new treatments, chronic infections were predicted to fall to 113 400 (94 900-132 400) by the end of 2018 and to 89 500 (71 300-108 600) by the end of 2020. Numbers developing severe HCV-related liver disease were predicted to fall by at least 24% from 2015 to 2020. Thus, we describe a coherent framework to monitor progress using routinely collected data, which can be extended to incorporate additional data sources. Planned treatment scale-up is likely to achieve 2020 WHO targets for HCV morbidity, but substantial efforts will be required to ensure that HCV testing and patient engagement are sufficiently high.

Long-term histological change in chronic hepatitis C patients who had received peginterferon plus ribavirin therapy with sustained virological response

BACKGROUND

The improvement in liver histology is an important aim in the management of hepatitis C virus (HCV) infection. Previous studies suggest that antiviral treatment could reduce the progression of hepatic fibrosis, especially in patients with sustained virological response (SVR). However, most studies were limited by short-term evaluations and the liver stiffness was assessed by non-invasive methods. In our study, we performed a paired liver biopsy study aimed at analyzing the long-term histological changes in patients with SVR.

METHODS

We included 31 patients who had been previously treated with peginterferon plus ribavirin. All patients achieved SVR and had received pre- and post-treatment liver biopsies. The histological appearance of fibrosis and inflammation were assessed with METAVIR scoring system and Histological Activity Index (HAI) criteria. We analyzed several factors associated with the histological response.

RESULTS

The median interval between two biopsies was 93.0 months. The percentage of patients with fibrosis regression, stable, and progression were 19%, 45%, and 36%. A total of 71% of patients achieved inflammation improvement, whereas 6% and 23% of patients had stable disease and disease-progression, respectively. We showed that the patients without baseline advanced fibrosis and those having a lower baseline HAI score had higher risk of fibrosis worsening. Baseline fibrosis and necroinflammation status did not influence HAI change significantly.

CONCLUSION

The progression of hepatic fibrosis and inflammation can be reversed in some patients who had long-term virological suppression. Patients with advanced baseline fibrosis and higher inflammatory stages seemed to receive more histologic benefit from successful antiviral treatments.

Tracing studies in cohorts with attrition: Selection models for efficient sampling

Cohort studies of chronic diseases involve recruitment and longitudinal follow-up of affected individuals with a view to studying the effect of risk factors on disease progression and death. When the time to withdrawal from the cohort is conditionally independent of the disease process the primary consequence is a loss of information on the parameters of interest. This loss can sometimes be mitigated through the conduct of tracing studies in which a subsample of those lost to follow up are contacted and some information is obtained on their disease and survival status. We describe the use of selection models to sample individuals for tracing who will yield more efficient estimators than those obtained by simple random sampling. Efficient sampling schemes featuring cost constraints are also developed and shown to perform well. An application to data from the University of Toronto Psoriatic Arthritis Cohort illustrates how to apply the method in a real setting.

Disease outcomes in a cohort of women in Ireland infected by hepatitis C-contaminated anti-D immunoglobulin during 1970s

BACKGROUND & AIM

In the mid-1990s, a group of Rh negative women was diagnosed with hepatitis C virus (HCV) genotype 1b infection, following administration of contaminated anti-D immunoglobulin in 1977-79. We aimed to describe their disease history and estimate the effect of selected host and treatment factors on disease progression.

METHODS

We conducted a cohort study on the women infected with HCV. Information was collected from records at seven HCV treatment centres on demographics, treatment and health outcomes up to the 31st December 2013. We calculated cumulative incidence, case fatality, and sub hazard ratios (SHR) for disease progression using competing risks regression.

RESULTS

Six hundred and eighty-two patients were included in the study. Among the chronically infected patients (n=374), 35% completed interferon-based antiviral treatment; 42% of whom had a sustained virological response. At the end of 2013, 19%, 1.9%, and 4.9% of chronically infected patients had developed cirrhosis, hepatocellular carcinoma, and liver-related death, respectively, compared with 10%, 0.8%, and 2.4% at the end of 2008. At the end of 2013, 321 (86%) of the chronically infected patients remained alive, 247 (77%) of whom were still chronically infected. Factors associated with increased cirrhosis rates included high alcohol intake (aSHR=4.9 [2.5-9.5]) and diabetes mellitus (aSHR=5.0 [2.9-8.8]).

CONCLUSIONS

Development of liver-related outcomes accelerated with time, with the risk of cirrhosis, hepatocellular carcinoma, and liver-related death doubling in the last five years of follow-up, particularly in women with high alcohol consumption and diabetes mellitus. We recommend that patients with chronic HCV infection be advised of the additive harmful effect of alcohol, and that data be collected on this cohort after a further five years to analyse the effect of subsequent antiviral treatment during this rapidly evolving period in HCV treatment history.

LAY SUMMARY

In the mid-1990s, a group of women were diagnosed with chronic hepatitis C virus (HCV) infection following receipt of contaminated anti-D immunoglobulin between 1977 and 1979 in Ireland. Seventy-two (19%) developed cirrhosis and 18 had died from liver-related causes (5%) after 36years of infection. Disease progression accelerated in the last five years of follow-up, particularly in women with diabetes mellitus and high alcohol consumption. We recommend that patients with chronic HCV infection be advised of the additive harmful effect of high alcohol consumption.

Sustained virological response halts fibrosis progression: A long-term follow-up study of people with chronic hepatitis C infection

BACKGROUND/AIMS

Long-term follow-up studies validating the clinical benefit of sustained virological response (SVR) in people with chronic hepatitis C (CHC) infection are lacking. Our aim was to identify rates and predictors of liver fibrosis progression in a large, well characterized cohort of CHC patients in whom paired liver fibrosis assessments were performed more than 10 years apart.

METHODS

CHC patients who had undergone a baseline liver biopsy pre-2004 and a follow up liver fibrosis assessment more than 10 years later (biopsy or liver stiffness measurement (LSM) using transient elastography [FibroScan]) were identified. Subjects who had undergone a baseline liver biopsy but had no follow up fibrosis assessment were recalled for LSM. Fibrosis was categorised as mild-moderate (METAVIR F0-2 / LSM result of ≤ 9.5 kPa) or advanced (METAVIR F3-4/ LSM >9.5 kPa). The primary objective was to assess the association between SVR and the rate of liver fibrosis progression over at least 10 years, defined as an increase from mild-moderate fibrosis at baseline liver biopsy (METAVIR F0-2) to advanced fibrosis at follow-up liver fibrosis assessment.

RESULTS

131 subjects were included in this analysis: 69% male, 82% Caucasian, 60% G1 HCV, 25% G3 HCV. The median age at F/U fibrosis staging was 57 (IQR 54-62) years with median estimated duration of infection 33-years (IQR 29-38). At F/U, liver fibrosis assessment was performed by LSM in 86% and liver biopsy in 14%. The median period between fibrosis assessments was 14-years (IQR 12-17). 109 (83%) participants had received interferon-based antiviral therapy. 40% attained SVR. At F/U, there was a significant increase in the proportion of subjects with advanced liver fibrosis: 27% at baseline vs. 46% at F/U (p = 0.002). The prevalence of advanced fibrosis did not change among subjects who attained SVR, 30% at B/L vs 25% at F/U (p = 0.343). However, advanced fibrosis became more common at F/U among subjects with persistent viremia: 10% at B/L vs 31% at F/U (p = 0.0001). SVR was independently associated with protection from liver fibrosis progression after adjustment for other variables including baseline ALT (p = 0.011), duration of HCV infection and mode of acquisition.

CONCLUSION

HCV eradication is associated with lower rates of liver fibrosis progression. The data support early treatment to prevent long-term liver complications of HCV infection.

Estimation of state occupancy probabilities in multistate models with dependent intermittent observation, with application to HIV viral rebounds

In follow-up studies on chronic disease cohorts, individuals are often observed at irregular visit times that may be related to their previous disease history and other factors. This can produce bias in standard methods of estimation. Working in the context of multistate models, we consider a method of nonparametric estimation for state occupancy probabilities that adjusts for dependent follow-up through the use of inverse-intensity-of-visit weighted estimating functions and smoothing. The methodology is applied to the estimation of viral rebound probabilities in the Canadian Observational Cohort on HIV-positive persons. Copyright © 2016 John Wiley & Sons, Ltd.

Optimal timing for hepatitis C therapy in US patients eligible for liver transplantation: a cost-effectiveness analysis

BACKGROUND

Recurrence of hepatitis C virus (HCV) following liver transplantation (LT) is universal for those with ongoing viraemia and is associated with higher rates of allograft failure and death. However, the optimal timing of HCV treatment for patients awaiting transplant remains unclear.

AIM

To evaluate the comparative cost-effectiveness of treating HCV pre-LT vs. post-LT (pre-emptive or after HCV recurrence).

METHODS

A Markov state-transition model was created to simulate the progression of a cohort of HCV-genotype 1 or 4 cirrhotic patients from the time of transplant listing until death. We then used this model to study the cost-effectiveness of ledipasvir-sofosbuvir (LDV/SOF) with ribavirin for 12 weeks, administered for three separate treatment strategies: (i) pre-LT; (ii) post-LT preemptively prior to HCV recurrence; or (iii) post-LT after HCV recurrence.

RESULTS

In the base-case analysis using a median model for end-stage liver disease (MELD) score <25 at the time of transplant, we found that pre-LT treatment of HCV led to more QALYs for fewer dollars compared to other strategies. Analysis limited to living donor LT recipients revealed that pre-LT treatment was also the most cost-effective strategy. When the analysis was repeated for MELD ≥25, decompensated disease (Child-Pugh class B or C), and hepatocellular carcinoma cases, preemptive post-LT strategy was more cost-effective.

CONCLUSIONS

Treatment of HCV prior to liver transplantation appears to be the most cost-effective strategy for patients with a MELD score <25. For patients with a MELD ≥25 or decompensated cirrhosis, preemptive post-liver transplantation treatment before HCV recurrence is the most cost-effective strategy.

Cost-Effectiveness Modelling of Sofosbuvir-Containing Regimens for Chronic Genotype 5 Hepatitis C Virus Infection in South Africa

BACKGROUND

The recently launched nucleotide polymerase inhibitor sofosbuvir represents a significant turn in the treatment paradigm of chronic hepatitis C. While effective, sofosbuvir is also associated with a considerable cost.

OBJECTIVE

The objective of this study was to evaluate the cost effectiveness of sofosbuvir-containing regimens in treatment-naive patients with chronic hepatitis C virus (HCV) genotype 5 (HCV-G5) mono-infection in South Africa (SA).

DESIGN

We constructed a lifetime horizon decision-analytic Markov model of the natural history of HCV infection to evaluate the cost effectiveness of sofosbuvir-ledipasvir (SOF/LDV) monotherapy against sofosbuvir triple therapy (SOF-TT) (sofosbuvir + pegylated interferon and ribavirin [peg-INF/RBV]) and the current standard of care (SOC) (peg-INF/RBV) for patients with chronic HCV-G5 in the South African context. The model was populated with data from published literature, expert opinion and South African private sector cost data. The price modelled for sofosbuvir was the predicted South African private sector price of 82,129.32 South African rand (R) (US$7000) for 12 weeks. The analysis was conducted from a third-party payer perspective.

OUTCOME MEASURES

The outcome measures were discounted and undiscounted costs (in 2015 South African rand and US dollars) and quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs).

RESULTS

Outcomes from the cost-effectiveness model show that SOF/LDV yields the most favourable future health economic outcomes compared with SOF-TT and the current SOC in SA. Findings relating to the lifetime incremental cost per QALY gained for patients infected with HCV-G5 indicate that SOF/LDV dominated both SOF-TT and SOC, i.e. SOF/LDV is less costly and more effective.

CONCLUSION

Outcomes from this analysis suggest that at a price of R123,190 ($US10,500) for 12 weeks of SOF/LDV might be cost effective for South African patients infected with HCV-G5.

Prevention of Hepatitis C by Screening and Treatment in U.S. Prisons

BACKGROUND

The prevalence of hepatitis C virus (HCV) in U.S. prisoners is high; however, HCV testing and treatment are rare. Infected inmates released back into society contribute to the spread of HCV in the general population. Routine hepatitis screening of inmates followed by new therapies may reduce ongoing HCV transmission.

OBJECTIVE

To evaluate the health and economic effect of HCV screening and treatment in prisons on the HCV epidemic in society.

DESIGN

Agent-based microsimulation model of HCV transmission and progression of HCV disease.

DATA SOURCES

Published literature.

TARGET POPULATION

Population in U.S. prisons and general community.

TIME HORIZON

30 years.

PERSPECTIVE

Societal.

INTERVENTIONS

Risk-based and universal opt-out hepatitis C screening in prisons, followed by treatment in a portion of patients.

OUTCOME MEASURES

Prevention of HCV transmission and associated disease in prisons and society, costs, quality-adjusted life-years (QALYs), incremental cost-effectiveness ratio (ICER), and total prison budget.

RESULTS OF BASE-CASE ANALYSIS

Implementing risk-based and opt-out screening could diagnose 41,900 to 122,700 new HCV cases in prisons in the next 30 years. Compared with no screening, these scenarios could prevent 5500 to 12,700 new HCV infections caused by released inmates, wherein about 90% of averted infections would have occurred outside of prisons. Screening could also prevent 4200 to 11,700 liver-related deaths. The ICERs of screening scenarios were $19,600 to $29,200 per QALY, and the respective first-year prison budget was $900 to $1150 million. Prisons would require an additional 12.4% of their current health care budget to implement such interventions.

RESULTS OF SENSITIVITY ANALYSIS

Results were sensitive to the time horizon, and ICERs otherwise remained less than $50,000 per QALY.

LIMITATION

Data on transmission network, reinfection rate, and opt-out HCV screening rate are lacking.

CONCLUSION

Universal opt-out HCV screening in prisons is highly cost-effective and would reduce HCV transmission and HCV-associated diseases primarily in the outside community. Investing in U.S. prisons to manage hepatitis C is a strategic approach to address the current epidemic.

PRIMARY FUNDING SOURCE

National Institutes of Health.

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.

Projections of the current and future disease burden of hepatitis C virus infection in Malaysia

Background

The prevalence of hepatitis C virus (HCV) infection in Malaysia has been estimated at 2.5% of the adult population. Our objective, satisfying one of the directives of the WHO Framework for Global Action on Viral Hepatitis, was to forecast the HCV disease burden in Malaysia using modelling methods.

Methods

An age-structured multi-state Markov model was developed to simulate the natural history of HCV infection. We tested three historical incidence scenarios that would give rise to the estimated prevalence in 2009, and calculated the incidence of cirrhosis, end-stage liver disease, and death, and disability-adjusted life-years (DALYs) under each scenario, to the year 2039. In the baseline scenario, current antiviral treatment levels were extended from 2014 to the end of the simulation period. To estimate the disease burden averted under current sustained virological response rates and treatment levels, the baseline scenario was compared to a counterfactual scenario in which no past or future treatment is assumed.

Results

In the baseline scenario, the projected disease burden for the year 2039 is 94,900 DALYs/year (95% credible interval (CrI): 77,100 to 124,500), with 2,002 (95% CrI: 1340 to 3040) and 540 (95% CrI: 251 to 1,030) individuals predicted to develop decompensated cirrhosis and hepatocellular carcinoma, respectively, in that year. Although current treatment practice is estimated to avert a cumulative total of 2,200 deaths from DC or HCC, a cumulative total of 63,900 HCV-related deaths is projected by 2039.

Conclusions

The HCV-related disease burden is already high and is forecast to rise steeply over the coming decades under current levels of antiviral treatment. Increased governmental resources to improve HCV screening and treatment rates and to reduce transmission are essential to address the high projected HCV disease burden in Malaysia.

Cost-effectiveness of non-invasive methods for assessment and monitoring of liver fibrosis and cirrhosis in patients with chronic liver disease: systematic review and economic evaluation

BACKGROUND

Liver biopsy is the reference standard for diagnosing the extent of fibrosis in chronic liver disease; however, it is invasive, with the potential for serious complications. Alternatives to biopsy include non-invasive liver tests (NILTs); however, the cost-effectiveness of these needs to be established.

OBJECTIVE

To assess the diagnostic accuracy and cost-effectiveness of NILTs in patients with chronic liver disease.

DATA SOURCES

We searched various databases from 1998 to April 2012, recent conference proceedings and reference lists.

METHODS

We included studies that assessed the diagnostic accuracy of NILTs using liver biopsy as the reference standard. Diagnostic studies were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Meta-analysis was conducted using the bivariate random-effects model with correlation between sensitivity and specificity (whenever possible). Decision models were used to evaluate the cost-effectiveness of the NILTs. Expected costs were estimated using a NHS perspective and health outcomes were measured as quality-adjusted life-years (QALYs). Markov models were developed to estimate long-term costs and QALYs following testing, and antiviral treatment where indicated, for chronic hepatitis B (HBV) and chronic hepatitis C (HCV). NILTs were compared with each other, sequential testing strategies, biopsy and strategies including no testing. For alcoholic liver disease (ALD), we assessed the cost-effectiveness of NILTs in the context of potentially increasing abstinence from alcohol. Owing to a lack of data and treatments specifically for fibrosis in patients with non-alcoholic fatty liver disease (NAFLD), the analysis was limited to an incremental cost per correct diagnosis. An analysis of NILTs to identify patients with cirrhosis for increased monitoring was also conducted.

RESULTS

Given a cost-effectiveness threshold of £20,000 per QALY, treating everyone with HCV without prior testing was cost-effective with an incremental cost-effectiveness ratio (ICER) of £9204. This was robust in most sensitivity analyses but sensitive to the extent of treatment benefit for patients with mild fibrosis. For HBV [hepatitis B e antigen (HBeAg)-negative)] this strategy had an ICER of £28,137, which was cost-effective only if the upper bound of the standard UK cost-effectiveness threshold range (£30,000) is acceptable. For HBeAg-positive disease, two NILTs applied sequentially (hyaluronic acid and magnetic resonance elastography) were cost-effective at a £20,000 threshold (ICER: £19,612); however, the results were highly uncertain, with several test strategies having similar expected outcomes and costs. For patients with ALD, liver biopsy was the cost-effective strategy, with an ICER of £822.

LIMITATIONS

A substantial number of tests had only one study from which diagnostic accuracy was derived; therefore, there is a high risk of bias. Most NILTs did not have validated cut-offs for diagnosis of specific fibrosis stages. The findings of the ALD model were dependent on assuptions about abstinence rates assumptions and the modelling approach for NAFLD was hindered by the lack of evidence on clinically effective treatments.

CONCLUSIONS

Treating everyone without NILTs is cost-effective for patients with HCV, but only for HBeAg-negative if the higher cost-effectiveness threshold is appropriate. For HBeAg-positive, two NILTs applied sequentially were cost-effective but highly uncertain. Further evidence for treatment effectiveness is required for ALD and NAFLD.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42011001561.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Increased uptake and new therapies are needed to avert rising hepatitis C-related end stage liver disease in England: modelling the predicted impact of treatment under different scenarios

BACKGROUND & AIMS

Hepatitis C (HCV) related disease in England is predicted to rise, and it is unclear whether treatment at current levels will be able to avert this. The aim of this study was to estimate the number of people with chronic HCV infection in England that are treated and assess the impact and costs of increasing treatment uptake.

METHODS

Numbers treated were estimated using national data sources for pegylated interferon supplied, dispensed, or purchased from 2006 to 2011. A back-calculation approach was used to project disease burden over the next 30 years and determine outcomes under various scenarios of treatment uptake.

RESULTS

5000 patients were estimated to have been treated in 2011 and 28,000 in total from 2006 to 2011; approximately 3.1% and 17% respectively of estimated chronic infections. Without treatment, incident cases of decompensated cirrhosis and hepatocellular carcinoma were predicted to increase until 2035 and reach 2290 cases per year. Treatment at current levels should reduce incidence by 600 cases per year, with a peak around 2030. Large increases in treatment are needed to halt the rise; and with more effective treatment the best case scenario predicts incidence of around 500 cases in 2030, although treatment uptake must still be increased considerably to achieve this.

CONCLUSIONS

If the infected population is left untreated, the number of patients with severe HCV-related disease will continue to increase and represent a substantial future burden on healthcare resources. This can be mitigated by increasing treatment uptake, which will have the greatest impact if implemented quickly.

Historical trends and projected hospital admissions for chronic hepatitis C infection in Canada: a birth cohort analysis

BACKGROUND

Much of the recent increase in hospital admission rates and mortality associated with hepatitis C in Canada is believed to be because of a higher prevalence of hepatitis C virus infection among those born between 1945 and 1965 (the baby boomer generation). We explored the effects of birth cohort on the rates of and projected trends in hospital admissions associated with hepatitis C.

METHODS

The hospital records of 17 344 inpatients with a diagnosis of chronic hepatitis C and liver disease, including liver cancer, were extracted from the Canadian Discharge Abstract Database for April 2004 to March 2011. For each 5-year birth cohort from 1915 to 1984, regression analysis was used to estimate the temporal trends associated with the average age of the cohort during the study period. Future hospital admissions were predicted based on the assumption that past trends would continue.

RESULTS

Hospital admissions associated with hepatitis C and liver disease increased an average of 6.0% (95% confidence interval [CI] 4.4%-7.7%) a year over the study period. As of 2010, hospital admission rates were highest for the 1950-1954 and 1955-1959 birth cohorts, at 17.6 (95% CI 13.2-23.5) and 13.7 (95% CI 10.3-18.2) times the rate for the 1970-1974 birth cohort. The corresponding same-age rate ratios predicted under a status quo scenario were 3.6 (95% CI 2.3-4.9) and 3.4 (95% CI 2.1-4.7). Same-age rate ratios were significantly higher for the four 5-year birth cohorts between 1950 and 1969 compared with other birth cohorts.

INTERPRETATION

Hospital admissions associated with chronic hepatitis C and liver disease were significantly higher for the 1950-1954 and 1955-1959 birth cohorts than for most other birth cohorts. Without further interventions, the disease burden associated with hepatitis C will continue to increase for most birth cohorts, likely peaking after age 70 years. The substantial disease burden emerging in younger birth cohorts should be monitored.

Ultrasound elastography for fibrosis surveillance is cost effective in patients with chronic hepatitis C virus in the UK

BACKGROUND

Chronic hepatitis C (HCV) is a significant risk factor for cirrhosis and subsequently hepatocellular carcinoma (HCC). HCV patients with cirrhosis are screened for HCC every 6 months. Surveillance for progression to cirrhosis and consequently access to HCC screening is not standardized. Liver biopsy, the usual test to determine cirrhosis, carries a significant risk of morbidity and associated mortality. Transient ultrasound elastography (fibroscan) is a non-invasive test for cirrhosis.

PURPOSE

This study assesses the cost effectiveness of annual surveillance for cirrhosis in patients with chronic HCV and the effect of replacing biopsy with fibroscan to diagnose cirrhosis.

METHOD

A Markov decision analytic model simulated a hypothetical cohort of 10,000 patients with chronic HCV initially without fibrosis over their lifetime. The cirrhosis surveillance strategies assessed were: no surveillance; current practice; fibroscan in current practice with biopsy to confirm cirrhosis; fibroscan completely replacing biopsy in current practice (definitive); annual biopsy; annual fibroscan with biopsy to confirm cirrhosis; annual definitive fibroscan.

RESULTS

Our results demonstrate that annual definitive fibroscan is the optimal strategy to diagnose cirrhosis. In our study, it diagnosed 20 % more cirrhosis cases than the current strategy, with 549 extra patients per 10,000 accessing screening over a lifetime and, consequently, 76 additional HCC cases diagnosed. The lifetime cost is £98.78 extra per patient compared to the current strategy for 1.72 additional unadjusted life years. Annual fibroscan surveillance of 132 patients results in the diagnosis one additional HCC case over a lifetime. The incremental cost-effectiveness ratio for an annual definitive fibroscan is £6,557.06/quality-adjusted life years gained.

CONCLUSION

Annual definitive fibroscan may be a cost-effective surveillance strategy to identify cirrhosis in patients with chronic HCV, thereby allowing access of these patients to HCC screening.

Quantifying the fraction of cirrhosis attributable to alcohol among chronic hepatitis C virus patients: implications for treatment cost-effectiveness

A substantial baseline risk of liver cirrhosis exists for patients with chronic hepatitis C virus (HCV) infection. However, the extent to which this could be driven by heavy alcohol use is unclear. Therefore, our principal aim was to determine the fraction of cirrhosis attributable to heavy alcohol use among chronic HCV patients attending a liver clinic. The study population comprised chronic HCV patients who had attended one of five liver clinics in Scotland during 1996-2010 and had (1) remained in follow-up for at least 6 months, (2) acquired HCV through either injecting drugs or blood transfusion, and (3) an estimated date of acquiring infection. Predictors of cirrhosis were determined from multivariate logistic regression. Regression parameters were used to determine the fraction of cirrhosis attributable to heavy alcohol use. Among 1,620 patients, 9% were diagnosed with cirrhosis, and 34% had ever engaged in heavy alcohol use (>50 units/week for a sustained period). Significant predictors of cirrhosis were age, duration of infection, and ever heavy alcohol use. The fraction of cirrhosis attributable to ever heavy alcohol use was 36.1% (95% confidence interval [CI]: 24.4-47.4). Moreover, among patients who had ever engaged in heavy alcohol use specifically, this attributable fraction exceeded 50% (61.6%; 95% CI: 47.0-72.2).

CONCLUSIONS

A substantial proportion of patients with chronic HCV develop liver cirrhosis as a consequence of heavy alcohol use. This has not been adequately acknowledged by cost utility analyses (CUAs). As such, estimates of cost-effectiveness may be exaggerated. Thus, these data are important to guide forthcoming CUAs in terms of taking better account of the factors leading to cirrhosis among patients with chronic HCV.

Improved hepatitis C treatment response in younger patients: findings from the UK HCV National Register cohort study

In a cohort of 272 treatment-naive individuals with chronic hepatitis C infection acquired on a known date who were enrolled in the UK HCV National Register, a progressive improvement in response to treatment was found with the evolution of antiviral therapies from 20% (25/122) for interferon monotherapy to 63% (55/88) for pegylated interferon+ribavirin therapy. Multivariable analysis results showed increasing age to be associated with poorer response to therapy [odds ratio (OR) 0·84, 95% confidence interval (CI) 0·72-0·99, P=0·03] whereas time since infection was not associated with response (OR 0·93, 95% CI 0·44-1·98, P=0·85). Other factors significantly associated with a positive response were non-type 1 genotype (P<0·0001) and combination therapies (P<0·0001). During the first two decades of chronic HCV infection, treatment at a younger age was found to be more influential in achieving a sustained viral response than treating earlier in the course of infection.

Reproductive status is associated with the severity of fibrosis in women with hepatitis C

Introduction

Chronic hepatitis C is the main cause of death in patients with end-stage liver disease. Prognosis depends on the increase of fibrosis, whose progression is twice as rapid in men as in women. Aim of the study was to evaluate the effects of reproductive stage on fibrosis severity in women and to compare these findings with age-matched men.

Materials and Methods

A retrospective study of 710 consecutive patients with biopsy-proven chronic hepatitis C was conducted, using data from a clinical database of two tertiary Italian care centers. Four age-matched groups of men served as controls. Data about demographics, biochemistry, liver biopsy and ultrasonography were analyzed. Contributing factors were assessed by multivariate logistic regression analysis.

Results

Liver fibrosis was more advanced in the early menopausal than in the fully reproductive (P<0.0001) or premenopausal (P = 0.042) group. Late menopausal women had higher liver fibrosis compared with the other groups (fully reproductive, P<0.0001; premenopausal, P = <0.0001; early menopausal, P = 0.052). Multivariate analyses showed that male sex was independently associated with more severe fibrosis in the groups corresponding to premenopausal (P = 0.048) and early menopausal (P = 0.004) but not late menopausal pairs. In women, estradiol/testosterone ratio decreased markedly in early (vs. reproductive age: P = 0.002 and vs. premenopausal: P<0.0001) and late menopause (vs. reproductive age: P = 0.001; vs. premenopausal: P<0.0001). In men age-matched with menopausal women, estradiol/testosterone ratio instead increased (reproductive age group vs. early: P = 0.002 and vs. late M: P = 0.001).

Conclusions

The severity of fibrosis in women worsens in parallel with increasing estrogen deprivation and estradiol/testosterone ratio decrease. Our data provide evidence why fibrosis progression is discontinuous in women and more linear and severe in men, in whom aging-associated estradiol/testosterone ratio increase occurs too late to noticeably influence the inflammatory process leading to fibrosis.

Impact of delayed diagnosis time in estimating progression rates to hepatitis C virus-related cirrhosis and death

Delay of the diagnosis of hepatitis C virus (HCV), and its treatment to avert cirrhosis, is often present sincethe early stage of HCV progression is latent. Current methods to determine the incubation time to HCV-related cirrhosis and the duration time from cirrhosis to subsequent events (e.g. complications or death) used to be based on the time of liver biopsy diagnosis and ignore this delay which led to an interval censoring for the first event time and a double censoring for the subsequent event time. To investigate the impact of this delay in estimating HCV progression rates and relevant estimating bias, we present a correlated two-stage progression model for delayed diagnosis time and fit the developed model to the previously studied hepatitis C cohort data from Edinburgh. Our analysis shows that taking the delayed diagnosis into account gives a mildly different estimate of progression rate to cirrhosis and significantly lower estimated progression rate to HCV-related death in comparison with conventional modelling. We also find that when the delay increases, the bias in estimating progression increases significantly.

Spontaneous loss of hepatitis C virus RNA from serum is associated with genotype 1 and younger age at exposure

A variety of factors have been associated with spontaneous loss of hepatitis C virus (HCV)-RNA from serum, including infecting HCV type, although results are conflicting. This study aimed to investigate further whether infecting HCV type was linked to spontaneous loss of HCV-RNA. Serum samples from 321 untreated HCV antibody positive patients presenting at the Hepatology clinic at Addenbrooke's Hospital, Cambridge between 2004 and 2007 were tested. These individuals were classified either as HCV antibody and HCV-RNA positive (viremic, n = 219) or HCV antibody positive and repeatedly HCV-RNA negative (non-viremic, n = 102). Infecting HCV type was identified by genotyping (viremic) or serotyping (non-viremic). Binomial regression analysis investigated the independent effect of HCV type on spontaneous loss of HCV-RNA from serum by comparing the two groups. Ninety-one percent of patients were found to be either genotype 1 or genotype 3. The prevalence of type 1 infection was greater among non-viremic (64.5%) than viremic individuals (45%). After controlling for the effects of potential confounding factors, multivariable analyses showed that individuals with type 1 infections were more likely to be non-viremic than genotype 3 infections (RR = 2.07; 95% CI: 1.25, 3.43; P = 0.005). Individuals infected at an older age were also less likely to become HCV-RNA negative spontaneously (RR = 0.42 comparing those infected at ≥20 years of age against those infected at <20 years of age, 95% CI: 0.25, 0.72; P = 0.002). In conclusion, the results suggest that HCV genotype 1 infections are more likely than genotype 3 infections to become spontaneously non-viremic, as are infections acquired at younger age.

Progression of initially mild hepatic fibrosis in patients with chronic hepatitis C infection

A significant number of patients with chronic hepatitis C infection have minimal fibrosis at presentation. Although the short-term outlook for such patients is good, there are limited data available on long-term progression. We assessed the risk of fibrosis progression in 282 patients with chronic hepatitis C with Ishak stage 0 or 1 fibrosis on initial liver biopsy. Progression of fibrosis stage occurred in 118 patients (42%) over a median interval of 52.5 months. Thirteen (5%) progressed to severe (Ishak stage 4 or more) fibrosis. Progression was significantly associated with both age at initial biopsy [odds ratio (OR) for progression of 1.31 per 10 year increase in age] and median alanine transaminase (ALT) levels during follow-up (OR of 1.06 per 10 IU/L increase). There was no significant association with gender, histological inflammatory grade, hepatic steatosis or body mass index. We conclude that hepatitis C with initially mild fibrosis does progress in a substantial proportion of patients and should not be viewed as a benign disease. Early antiviral therapy should be considered in older patients and those with high ALT levels.

Prognosis of hepatitis C virus-infected Canadian post-transfusion compensation claimant cohort

Accurate prognostic estimates were required to ensure the sufficiency of the $1.1 billion compensation fund established in 1998 to compensate Canadians who acquired hepatitis C virus (HCV) infection through blood transfusion between 1986 and 1990. This article reports the application of Markov modelling and epidemiological methods to estimate the prognosis of individuals who have claimed compensation. Clinical characteristics of the claimant cohort (n = 5004) were used to define the starting distribution. Annual stage-specific transition probabilities (F0-->F1, . . ., F3-->F4) were derived from the claimants, using the Markov maximum likelihood estimation method. HCV treatment efficacy was derived from the literature and practice patterns were estimated from a national survey. The estimated stage-specific transition probabilities of the cohort between F0-->F1, F1-->F2, F2-->F3 and F3-->F4 were 0.032, 0.137, 0.150 and 0.097 respectively. At 20 years after the index transfusion, approximately 10% of all living claimants (n = 3773) had cirrhosis and 0.5% developed hepatocellular carcinoma (HCC). For nonhaemophilic patients, the predicted 20-year (2030) risk of HCV-related cirrhosis was 23%, and the risk of HCC and liver-related death was 7% and 11% respectively. Haemophilic patients who are younger and are frequently co-infected with human immunodeficiency virus would have higher 20-year risks of cirrhosis (37%), HCC (12%) and liver-related death (19%). Our results indicate that rates of progression to advanced liver disease in post-transfusion cohorts may be lower than previously reported. The Canadian post-transfusion cohort offers new and relevant prognostic information for post-transfusion HCV patients in Canada and is an invaluable resource to study the natural history and resource utilization of HCV-infected individuals in future studies.

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.

Cost-effectiveness of pegylated interferon and ribavirin for patients with chronic hepatitis C treated in routine clinical practice

OBJECTIVES

This study assesses whether pegylated interferon and ribavirin is cost-effective compared with no antiviral treatment provided in routine clinical practice, for different patient subgroups.

METHODS

The cost-effectiveness analysis (CEA) uses a Markov decision model to estimate the lifetime cost per quality-adjusted life-year (QALY) of antiviral treatment compared with no treatment. The model is populated with data on sustained virological responses, costs, and transition probabilities all taken from a large representative sample of UK cases and centers (Trent HCV database).

RESULTS

The CEA found that pegylated interferon and ribavirin was cost-effective for most patient subgroups. The CEA found that for patients with genotype non-1, the intervention led to cost reductions and gains of at least 0.5 QALYs. For genotype 1 cases with mild or moderate disease, and younger cirrhotic patients (aged 40 or less), costs per QALY remained below 20,000 pound sterling ($40,000 or 29,000 euro). For genotype 1 cases with cirrhosis aged 50, the mean cost per QALY rose to over 60,000 pound sterling ($120,000 or 87,000 euro).

CONCLUSIONS

The study concludes that, based on cost and effectiveness data collected from routine clinical practice, treatment with pegylated interferon and ribavirin is generally cost-effective. The study shows that there are variations according to patient subgroup and for older (aged 50 or over) genotype 1 patients with cirrhosis, antiviral treatment appears less cost-effective.

The cost-effectiveness of screening and treatment for hepatitis C in prisons in England and Wales: a cost-utility analysis

Prisoners have a high prevalence of hepatitis C virus (HCV) infection compared with the general population in England and Wales and in many locations throughout the world. This is because of large numbers of injecting drug users that engage in behaviours likely to transmit HCV being present within prison populations. It is, therefore, suggested that prison may be an appropriate location for HCV screening and treatment to be administered. Using cost-utility analysis, this study considers the costs and benefits of administering a single round of screening on reception into prison to all individuals followed by possible later screening in the community and comparing this to individuals who may only be tested and treated in the community at a later date. The cost/QALY of one round of prison testing and treatment was found to be 54,852 pounds sterling, although probabilistic sensitivity analysis showed extensive uncertainty about this estimate. One-way sensitivity analysis revealed the importance of the parameters describing the progression of chronic HCV and the discount rates. While the results presented here at baseline would suggest that screening and treatment for HCV in prisons is not cost-effective, these results are subject to much uncertainty. The importance of the rates describing the progression of chronic HCV on the cost-effectiveness of this intervention has been demonstrated and this suggests that future work should be undertaken to gain further insight into the rates that individuals progress to the later stages of chronic HCV infection.

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.

Response rates to combination therapy for chronic HCV infection in a clinical setting and derivation of probability tables for individual patient management

Evidence for efficacy of established treatment guidelines for chronic hepatitis C virus (HCV) disease is based on multinational randomized controlled trials (RCTs). Strategies for managing HCV, however, require an assessment of the effectiveness of intervention in routine clinical practice. We report the outcomes of combination therapy in a large cohort of HCV-infected individuals in the UK. A total of 347 (113 genotype 1, 234 genotype non-1) patients were treated with pegylated interferon and ribavirin according to current guidelines. Forty-two (37.2%) of those with genotype 1 infection and 164 (70.1%) with genotype non-1 infection achieved sustained viral response (SVR). Thirty-nine (11%) patients withdrew from treatment. In addition to viral genotype, factors predictive of a response to therapy were age at start of treatment and disease stage on pretreatment liver biopsy. Multivariate regression analysis demonstrated that the effects of age [odds ratio 0.5; 95% confidence interval (0.31-0.82) per 10-year increment (P = 0.006)] were confined to genotype 1 disease. In order to further inform the management of the individual patient, a multivariate logistic model was used to predict the probability of SVR for subgroups defined by disease stage, genotype and age at commencement of therapy. This model revealed striking differences in predicted response rates between subgroups and provided a strong rationale for early treatment, particularly for those with genotype 1 disease. Our study demonstrates that results comparable with those of RCTs can be achieved in clinical practice, and suggests that prediction of response rates based on probability modelling will provide a valuable adjunct to individual patient management.

Event-biased referral can distort estimation of hepatitis C virus progression rate to cirrhosis, and of prognostic influences

OBJECTIVE

To investigate how cirrhosis-biased referral to liver clinics can explain the wide variation in progression rates for differently recruited cohorts and, in particular, for liver clinic cohorts compared to community-based studies of the natural history of hepatitis C virus (HCV).

STUDY DESIGN AND SETTING

A simulation was designed to illustrate the sort of referral bias pattern that is capable of converting a 20-year progression rate to cirrhosis of around 5% in the community of HCV-infected individuals into a 20% progression rate for patients who have been selectively referred to a liver clinic.

RESULTS

We show that event-biased recruitment, such as occurs if referral to liver clinics is increasingly likely the closer a patient is to cirrhosis, can produce severely upwardly biased estimates of progression rates, can dampen the influence of "poor prognostic" factors (such as history of excessive alcohol consumption), but overrepresents the proportion of patients in the community of HCV-infected individuals who have poor prognosis.

CONCLUSION

When attempting to establish the natural history of new diseases with long incubation periods, researchers should be on the look out for potential biases that result from the way patients are referred into clinical cohorts.

The burden of hepatitis C in England

In England, a large number of individuals are infected with the hepatitis C virus (HCV) and may develop future liver complications, such as decompensated cirrhosis and hepatocellular carcinoma (HCC). Estimates of the magnitude of this future burden are required to plan healthcare resources. We have estimated past incidence of HCV infection in England and predict future burden of end-stage liver disease in the HCV-infected population. A model of the natural history of HCV as a series of disease stages was constructed. A back-calculation approach was performed, using the natural history model and data on annual HCC deaths in England from 1996 to 2004 with mention of HCV and hospital episode statistics for end-stage liver disease with HCV. The number of HCV-infected people living with compensated cirrhosis is predicted to rise from 3705 [95% credible interval (CrI): 2820-4975] in 2005 to 7550 (95% CrI: 5120-11,640) in 2015. The number of decompensated cirrhosis and/or HCC cases is also predicted to rise, to 2540 (95% CrI: 2035-3310) by 2015. HCV incidence increased during the 1980s, with an annual incidence of 12 650 (95% CrI: 6150-26,450) by 1989. HCV-related cirrhosis and deaths from HCC in England are likely to increase dramatically within the next decade. If patients are left undiagnosed and untreated, the future burden of the disease on healthcare resources will be substantial.