Trends in Utilization and Costs Following a Hepatitis C Elimination Initiative.

Importance: Expanded screening and treatment options as part of national guidelines and statewide policy initiatives have the potential to eliminate hepatitis C virus (HCV). Objective: To describe trends in HCV screening, prevalence, treatment, and costs before and after Washington State's HCV elimination initiative. Design, Setting, and Participants: This case series is an observational analysis of retrospective claims data aggregated at the individual-month level. The dataset included individuals in the Washington State All Payers Claims Database between January 2017 and September 2022. Analyses were conducted from August to November 2025. Exposures: In July 2019, as part of a directive from the governor, the Washington State Department of Health released a comprehensive HCV elimination strategy. The plan included discounted and subscription-based payment models and removal of restrictive prior authorization and specialist consultation requirements. Main Outcomes and Measures: International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) and Current Procedural Terminology codes were used to identify HCV testing or screening, ICD-10 diagnosis codes were used for HCV infections, and the National Drug Codes were used for HCV direct-acting antiviral medications. An individual was considered to have newly diagnosed HCV at the earliest month in which they had an HCV test claim followed by 2 HCV diagnosis codes within the subsequent 12 months and no HCV diagnosis during the 6 months before the test month. Total health care costs per month were computed, excluding cost of HCV direct-acting antiviral medications. Interrupted time-series approaches computed trends over time using the second quarter (Q2) of 2019 as a reference time point. Results: More than 21 million unique individuals (mean [SD] age, 44 [26] years; 11 085 080 female [53%]) were included in the data extraction. The number of HCV tests per month was stable during the preinitiative and immediate postinitiative period. Beginning in 2020 Q3, screening increased significantly from the reference quarter by 10.5 additional tests per month per 1000 Washington enrollees (95% CI, 8.8 to 12.2 tests per month per 1000 enrollees; P < .001). Consistent with increased screening, the prevalence of chronic HCV cases increased through 2021, but declined by 0.4 cases per 1000 enrollees comparing 2019 Q2 to 2022 Q3 (95% CI, -0.6 to -0.2 cases per 1000 enrollees; P < .001). The proportion of newly diagnosed cases receiving any HCV treatment increased from 16.8% (634 of 3776 cases) in 2017 to 24.9% (472 of 1894 cases) in early 2021 (difference, 8.1 percentage points; 95% CI, 5.8 to 10.4 percentage points; P < .001), but slopes before and after 2019 Q2 were not significantly different. Costs per ever prevalent case decreased significantly by 2021 Q1 (-$520 per month compared with 2019 Q2; 95% CI, -$922 to -$124 per month; P = .01). Conclusions: In this longitudinal case series analysis of claims data, Washington State's elimination initiative, combined with revised national screening guidelines and improved treatment options, contributed to expansion of HCV screening and changes over time in the proportion of people identified and treated for HCV, as well as decreased overall care costs.