Hepatitis C active viremia over time in an ED-based testing programme: Impact, disparities and surveillance tool.

Hepatitis C virus (HCV) surveillance is a critical component of a comprehensive strategy to prevent and control HCV infection and HCV-related chronic liver disease. The emergency department (ED) has been increasingly recognized as a vital partner in HCV testing and linkage. We sought to consider active RNA HCV viremia over time in patients participating in an ED-based testing programme as a measure of local HCV surveillance and as a barometer of ED-testing programme impact. We performed a retrospective analysis of individuals participating in our ED-based HCV testing programme between 2015 and 2021. Chi-square tests were used to compare the demographic characteristics of HCV antibody positive tests with active viremia to those without active viremia. Cox proportional hazard models were used to estimate the trend in active viremia risk over time in the overall study population as well as in key subpopulations of interest. Of 5456 HCV antibody positive individuals, 3102 (56.8%) had active viremia. In the overall study population, we found that the risk of active viremia decreased by 4.8% per year during the study period (RR: 0.95, 95% CI: 0.93-0.97|p < .0001). Baby boomers experienced a 9% decrease in active viremia risk per year over the study period while non-baby boomers only had a 2% decrease in risk per year (p = .0009). Compared with insured patients, uninsured patients had a smaller decrease in risk of active HCV viremia per year (p = .003). No significant differences in the risk of active viremia over time were observed for gender (p = .4694) or by primary care provider status (p = .2208). In conclusion, this ED-based testing and linkage programme demonstrates significantly decreased active HCV viremia over time. It also highlights subpopulations, specifically non-baby boomers and uninsured patients, who may benefit from focused interventions to improve access to and adoption of definitive HCV care.