Effectiveness and cost-effectiveness of interventions targeting harm reduction and chronic hepatitis C cascade of care in people who inject drugs: The case of France.

Direct-acting antivirals (DAAs) represent an opportunity to improve hepatitis C virus (HCV) care cascade. This combined with improved harm reduction interventions may lead to HCV elimination especially in people who inject drugs (PWID). We assessed the effectiveness/cost-effectiveness of improvements in harm reduction and chronic hepatitis C (CHC) care cascade in PWID in France. We used a dynamic model of HCV transmission and CHC natural history and evaluated the following: improved needle/syringe programmes-opioid substitution therapies, faster diagnosis/linkage to care, earlier treatment initiation, alone and in combination among active PWID (mean age = 36). Outcomes were as follows: life expectancy in discounted quality-adjusted life years (QALYs); direct lifetime discounted costs; incremental cost-effectiveness ratio (ICER); number of infections/reinfections. Under the current practice, life expectancy was 15.846 QALYs, for a mean lifetime cost of €20 762. Treatment initiation at F0 fibrosis stage alone was less effective and more costly than faster diagnosis/linkage to care combined with treatment initiation at F0, which increased life expectancy to 16.694 QALYs, decreased new infections by 37%, with a ICER = €5300/QALY. Combining these interventions with harm reduction improvements was the most effective scenario (life expectancy = 16.701 QALYs, 41% decrease in new infections) but was not cost-effective (ICER = €105 600/QALY); it became cost-effective with higher initial HCV incidence rates and lower harm reduction coverage than in our base-case scenario. This study illustrated the high effectiveness, and cost-effectiveness, of a faster diagnosis/linkage to care together with treatment from F0 with DAAs. This "Test and treat" strategy should play a central role both in improving the life expectancies of HCV-infected patients, and in reducing HCV transmission.

Dynamic modelling of hepatitis C virus transmission among people who inject drugs: a methodological review.

Equipment sharing among people who inject drugs (PWID) is a key risk factor in infection by hepatitis C virus (HCV). Both the effectiveness and cost-effectiveness of interventions aimed at reducing HCV transmission in this population (such as opioid substitution therapy, needle exchange programmes or improved treatment) are difficult to evaluate using field surveys. Ethical issues and complicated access to the PWID population make it difficult to gather epidemiological data. In this context, mathematical modelling of HCV transmission is a useful alternative for comparing the cost and effectiveness of various interventions. Several models have been developed in the past few years. They are often based on strong hypotheses concerning the population structure. This review presents compartmental and individual-based models to underline their strengths and limits in the context of HCV infection among PWID. The final section discusses the main results of the papers.