Estimation of chronic hepatitis C and future burden using various treatment scenarios

Thesis (Master's)--University of Washington, 2021Background Hepatitis C is considered a major public health threat.1,2 In 2016, the World Health Organization Global Health Sector Strategy (WHO-GHSS) adopted goals to eliminate hepatitis as a global health concern by 2030. One proxy measurement of goal achievement is a 80% reduction in viremia prevalence of chronic hepatitis C between 2015 and 2030.3 Given improvements in treatment regimens, countries have unique opportunities to functionally cure those chronically infected with HCV and prevent progression to liver cancer and cirrhosis.4 This study identified hepatitis C treatment data sources, created a standardized data processing and application model, and evaluated the impact of treatment both within the Global Burden of Disease Study (GBD) and on future burden of chronic hepatitis C in 31 locations.Methods This study used treatment data and estimates of chronic hepatitis C from the Global Burden of Disease Study 2020. Treatment data are processed through multi-step processing: multi-year splitting, both-sex splitting into sex-specific data points, age-splitting into 5 year GBD age groups, and application of treatment efficacy. Next, the cumulative effect of treatment is calculated as the summation of treatment in the current year as well as previous years and age groups. To generate final GBD estimations of chronic hepatitis C, the number treated by age, sex, year, and location are subtracted from the counterfactual, or unadjusted, treatment estimates of chronic hepatitis C. Three future treatment scenarios are evaluated to explore future burden of chronic hepatitis C: sustained proportion, maximum absolute treatment, and using Egypt’s 2019 mass-treatment campaign as an exemplar for proportional reduction. Results This study found that in 2020 the number of chronic hepatitis C prevalent cases across the 31 locations estimated was 60.5 million (95% uncertainty interval [UI] 46.3 – 78.9). Under the unadjusted model/counterfactual scenario of no treatment, in 2020, the number of chronically infected individuals was 66.9 million (52.4 – 85.4). There was a 10.6% difference (8.3 – 13.2) between the counterfactual and adjusted GBD estimates. In the no treatment scenario, in 2030, 74.0 million (58.0 - 94.4) persons would be infected with chronic hepatitis C. Under the three scenarios of sustained, maximum treated, and exemplar, prevalence would decrease between 2015 and 2030. The largest decline under the various scenarios would be seen in the exemplar scenario in which there is a 58.1% (-66.3 to -48.4) reduction between 2015 and 2030. Interpretation Input data and modeling strategies related to hepatitis C treatment play an important role in accurate estimation of the burden of chronic hepatitis C. Future studies should identify additional data sources to improve data coverage. Regression methods can be used to estimate treatment coverage even in the absence of treatment data. Additionally, findings on future treatment scenarios indicates that continuation of current treatment will result in decreases in the burden of chronic hepatitis C by 2030. However, to achieve the WHO-GHSS goal of 80% reduction, locations must increase treatment over the next decade