Theme: Epidemiology & Public Health Research Year: 2017
Background: People who inject drugs (PWID) are one of the key high-risk groups for hepatitis C virus (HCV), yet only ~50% of PWID are currently screened for HCV in Switzerland. This study investigated the cost-effectiveness of expanding screening and subsequent treatment in former and active PWID using rapid antibody saliva tests (Oraquick®; OraSure Technologies, Bethlehem, PA) and dried blood spot (DBS) testing (semi-quantitative viremia and viral genotype), and treatment with recently launched therapies which have higher cure rates and shorter treatment courses.
Methods: A comprehensive strategy offering annual screening to all IDUs via rapid antibody saliva and DBS tests in specialized centres was compared to the current strategy of screening in general practice via venepuncture. A decision tree simulated the diagnosis pathway, with prevalence and behavioural effects on secondary transmission rates as scenario analyses, and results from a Markov model were included to incorporate treatment effects and natural progression over a lifetime time-horizon. Inputs were derived from clinical studies, literature reviews and expert opinion. The net monetary benefit and incremental cost-effectiveness ratio (ICER) of comprehensive versus current screening were calculated. Deterministic and probabilistic sensitivity analyses explored parameter uncertainty and whether variations in inputs informed by expert opinion changed the cost-effectiveness results.
Results: At a willingness-to-pay threshold of CHF 100,000 (USD 99,283) per quality-adjusted life-year (QALY), comprehensive screening had a 91% probability of being cost-effective (corresponding ICER CHF 5,910/QALY [USD 5,868/QALY]). The ICER reduced to CHF 2,114/QALY (USD 2,099/QALY) if behavioural and prevalence effects on transmission were included. Results were most sensitive to the respective HCV prevalence in the current and comprehensive screening populations, and testing uptake rates. Furthermore, the cost-effectiveness of comprehensive screening increased with the underlying population prevalence.
Conclusion: Increasing screening uptake via rapid saliva and DBS testing is likely to be worthwhile in addressing HCV prevalence in high-risk populations such as PWID.
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