Title: Assessing the impact and cost-effectiveness of needle/syringe provision on hepatitis C transmission among people who inject drugs: an analysis of pooled datasets and economic modelling
Funder: Department of Health (England)

Abstract: While there is good evidence that needle and syringe programmes (NSP) and opiate substitution treatment (OST) in combination reduce injecting risk behaviours and some evidence to show their impact on HIV incidence there is little evidence for their impact on hepatitis C (HCV) incidence among people who inject drugs (PWID). There have been no economic evaluations of NSPs undertaken in Western Europe and few have considered the costs saved due to care and treatment averted. All existing studies have relied on weak measures of NSP effectiveness with most using changes in self reported risk behaviour which can be biased. This project will fill a gap in the evidence by providing robust estimates of the efficacy of NSP and OST on reducing an individual’s risk of HCV transmission and an understanding of the likely impact of existing coverage levels of NSP and changes in the extent of provision. It will also produce the first assessment of the cost-effectiveness of needle/syringe provision in UK and will estimate the costs and incremental cost-effectiveness ratio associated with increasing coverage on HCV transmission among PWID.The project will answer the following research questions: 1.What is the impact of different coverage levels of needle/syringe provision on the incidence of hepatitis C among PWID at the individual level?2.What are the contribution of other risk factors on HCV incidence and the overall transmission of HCV among PWID?3.What is the international evidence on the impact of NSPs with and without OST on incidence of hepatitis C among PWID?4.What are the costs associated with existing NSP provision in three UK settings?5.What is the impact and cost-effectiveness of existing provision of NSP compared to no provision on HCV and HIV transmission and disease burden among PWID in three UK settings?6.What are the possible strategies for increasing the coverage of NSP provision in three UK settings and likely impact and cost-effectiveness of these strategies?The participants under study are PWID. The intervention to be evaluated is NSPs and coverage of the intervention will be measured by calculating the total number of needle/syringes received per month by a PWID divided by their frequency of injections. NSPs in England are funded through drug Action Teams (DATs) and Local Strategic Partnerships – multi-agency bodies involving local government police and health services and can be provided through pharmacies mobile vans or specialist fixed sites. We will compare PWID with different coverage levels of NSP provision. The outcome of interest is new HCV infections defined as being antibody negative and RNA positive in Polymerase Chain Reaction testing.Three linked data collection activities and analyses will be undertaken: 1.Analysis of pooled data (RQ 1 2)Data will be collated from the unlinked anonymous monitoring (UAM) survey of PWID (England Wales and Northern Ireland) the Australian Needle/Syringe Programme Survey (ANSPS) the Needle Exchange Surveillance Initiative (NESI) and studies of community-recruited PWID. All sources contain comparable indicators on intervention use and new cases of HCV except for UAM from which 1800 antibody negative dried-blood spots will be tested. Approximately 13500 observations will be included of which ~6400 will be anti-HCV negative and ~160 recent infections. We will analyse the pooled data sets using logistic regression to model the odds of recent infection by NSP exposure adjusting for key confounders (injecting duration gender crack use and homelessness) and assessing joint effects of NSP and OST. We will explore evidence of a dose-response relationship and linear decrease in the odds of infection with increasing NSP coverage and examine the impact of OST. 2. Systematic Review (RQ3)We will conduct a systematic review following Cochrane Guidelines of published studies and unpublished analyses that report on the effect of NSP exposure and/or OST on HCV incidence. We will conduct a meta-analysis to estimate the unadjusted effects of NSP exposure and/or OST on HCV incidence incorporating the pooled analysis results to determine the generalisability of findings to other settings. 3. Modelling Impact and Economic evaluation (RQ 4-6)An existing dynamic deterministic model of HIV and HCV transmission and OST/NSP intervention coverage among PWID will be adapted. Intervention efficacy estimates will come from the pooled analysis. The model will be used to estimate the impact of historical and current NSP coverage levels for reducing HIV and HCV prevalence and disease burden in three UK settings and future impact of increasing or decreasing NSP coverage levels. The model will also estimate the population attributable fraction of different behavioural risk factors for increasing HCV transmission in these settings. We will estimate the cost-effectiveness of current NSP provision compared to no provision and the potential cost-effectiveness of increasing NSP coverage in each setting compared to maintaining stable coverage. Data on resource use and costs of existing NSP provision will be collected from each setting including staff time salaries training equipment and overheads and will be combined with modeled impact estimates. Following a review of the literature discussions will be held with collaborators and other stakeholders to develop modeling scenarios for strategies that could improve NSP coverage. Costs will be modeled based on the cost data collected from each site and the effect of changes or differences in NSP provision will be obtained from the literature or from settings that have changed attributes of their NSP provision or by comparing between sites with differences in provision.


Research activity codes: 3.1 PRIMARY PREVENTION INTERVENTIONS TO MODIFY BEHAVIOURS OR PROMOTE WELL-BEING
Health categories: INFECTION