Health and Economic Impact of Periodic Hepatitis C Virus Testing Among People Who Inject Drugs.

Importance: Periodic hepatitis C virus (HCV) testing is recommended for people who inject drugs (PWID), but the optimal testing frequency remains unknown. Objective: To evaluate the health benefits, costs, and cost-effectiveness of alternative HCV testing frequencies for PWID. Design, Setting, and Participants: This cost-effectiveness analysis extended a previously published agent-based network simulation model of HCV transmission through the sharing of injection equipment among PWID. Network-based HCV transmission was calibrated to longitudinal data from the Social Networks Among Appalachian People study and published literature on PWID networks in the US to evaluate HCV testing strategies in both a sparse PWID network setting with lower HCV transmission and a dense network setting with higher HCV transmission. Data were collected from November 2008 to August 2010, and data were analyzed from September 2017 to December 2019. Exposures: Periodic HCV testing and treatment, with alternative average testing frequencies among PWID who have access to and use HCV care. Main Outcomes and Measures: Changes in cumulative quality-adjusted life-years (QALYs) and health care costs over 60 years (in 2021 US dollars) and incremental cost-effectiveness ratios (ICERs) discounted at 3% annually. Results: The mean initial age of 1552 simulated PWID was 32 years. Compared with no testing, HCV testing and treatment among PWID over a 10-year intervention period increased QALYs by 2.5% to 4.6% and costs by 0.5% to 2.3% across average testing frequencies ranging from once every 2 years to once monthly. In a lower transmission setting, testing every 2 years was weakly dominated by more frequent testing strategies; testing every year, every 6 months, every 3 months, and every month had ICERs of $6000 per QALY, $9300 per QALY, $24 200 per QALY, and $138 400 per QALY, respectively. In a higher transmission setting, testing every 2 years and every year were both weakly dominated, while testing every 6 months, every 3 months, and every month had ICERs of $14 000 per QALY, $30 100 per QALY, and $93 300 per QALY, respectively. Results were sensitive to risks of primary infection and reinfection as well as access to and utilization of HCV testing services among PWID. Conclusions and Relevance: In this economic evaluation study, based on common benchmarks for cost-effectiveness, frequent HCV testing among PWID was cost-effective in both lower and higher transmission settings.