Background: Hepatitis C virus (HCV) elimination requires a thorough understanding of the care cascade. A direct-acting-antiviral (DAA)-era description of the care cascade has not been undertaken in Ontario, Canada. Our primary objective was to describe the current population-level care cascade in the general Ontario population and among key risk-groups ─ baby-boomers, immigrants, and individuals experiencing residential instability. The secondary objective was to identify predictors of engagement. Methods: We conducted a population-based cohort study of Ontario residents undergoing HCV testing between January 1, 1999, and December 31, 2018, and mapped the care cascade [antibody diagnosed, RNA tested, RNA positive, genotyped, treated, achieved sustained virologic response (SVR), reinfected/relapsed] as of December 31, 2018. The cascade was stratified by risk groups. Cause-specific hazard modeling was used to identify demographic, and socioeconomic predictors of engagement with key steps of the cascade. Results: Among 108,428 Ontario residents living with an HCV antibody diagnosis, 88% received confirmatory RNA testing; of these, 62% tested positive and 94% of positive tests were genotyped. Of those with confirmed viremia, 53% initiated treatment, and 76% of treated individuals achieved SVR, while ~1% experienced reinfection or relapse. Males, older birth cohorts, long-term residents, those with a history of substance use disorder and social marginalization (e.g., material deprivation, residential instability), and those initially diagnosed in the pre-DAA era exhibited lower rates of engagement with almost every step of HCV care. Conclusions: Despite DAA-era improvements, treatment initiation remains a major gap. HCV screening and linkage-to-treatment, particularly for those with a history of substance use disorder and social marginalization, will be needed to equitably close gaps in HCV care in Ontario.

Dr. W Wong reports a grant from the Canadian Liver Foundation, outside the submitted work.

This study was supported by ICES, which is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care (MOHLTC). A. Erman is supported by a postdoctoral fellowship from the Canadian Institute of Health Research (CIHR) [FRN:201910MFE-430962-169632]. This research was supported, in part, by a Canada Research Chair in Economics of Infectious Diseases held by Beate Sander [CRC-950-232429]. This study also received funding from CIHR grant [PJT-156066]. The analyses, conclusions, opinions, and statements expressed herein are solely those of the authors and do not reflect those of the funding or data sources; no endorsement is intended or should be inferred

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