Forecasting Hepatitis C liver disease burden on real-life data. Does the hidden iceberg matter to reach the elimination goals?

Abstract

Background & aims: Advances in direct-acting antiviral treatment of HCV have reinvigorated public health initiatives aimed at identifying affected individuals. We evaluated the possible impact of only diagnosed and linked-to-care individuals on overall HCV burden estimates and identified a possible strategy to achieve the WHO targets by 2030.

Methods: Using a modelling approach grounded in Italian real-life data of diagnosed and treated patients, different linkage-to-care scenarios were built to evaluate potential strategies in achieving the HCV elimination goals.

Results: Under the 40% linked-to-care scenario, viraemic burden would decline (60%); however, eligible patients to treat will be depleted by 2025. Increased case finding through a targeted screening strategy in 1948-1978 birth cohorts could supplement the pool of diagnosed patients by finding 75% of F0-F3 cases. Under the 60% linked-to-care scenario, viraemic infections would decline by 70% by 2030 but the patients eligible for treatment will run out by 2028. If treatment is to be maintained, a screening strategy focusing on 1958-1978 birth cohorts could capture 55% of F0-F3 individuals. Under the 80% linked-to-care scenario, screening limited in 1968-1978 birth cohorts could sustain treatment at levels required to achieve the HCV elimination goals.

Conclusion: In Italy, which is an HCV endemic country, the eligible pool of patients to treat will run out between 2025 and 2028. To maintain the treatment rate and achieve the HCV elimination goals, increased case finding in targeted, high prevalence groups is required.

Keywords: HCV; WHO; chronic infection; linkage to care.

Figure 1

Total viraemic infections by scenario, 2015‐2030. The forecasted total number of viraemic infections by Base 2016, PITER linkage‐to‐care and WHO Targets scenarios were compared. By 2030, total viraemic infections are expected to decline due to the higher treatment rate in Italy. However, the number of remaining infections would still remain high in each scenario. The WHO Scenario is forecasted to have the largest reduction on overall viraemic infections

Figure 2

Liver‐related morbidity and mortality by scenario, 2015‐2030. The forecasted liver‐related outcomes by Base 2016 and WHO Targets scenarios were compared. By 2030, all HCV‐related outcomes are expected to decline due to the higher treatment rate in Italy. However, the WHO Scenario is forecasted to have the largest impact on liver‐related outcomes

Figure 3

Sensitivity analysis of key drivers of uncertainty in the Italy Polaris model (A) and in the PITER adjusted model (B) in 2030 forecasted viraemic HCV prevalence (top ten shown). The labels refer to the high and low value of the variable under consideration. For the Italy Polaris model, the uncertainty in new infections considered in the model had the largest effect on the 2030 forecast of prevalent viraemic infections. The uncertainty in transition probabilities and standardized mortality ratio due to a history of blood transfusion (see also Section 1 in Appendix S1) accounted for more than 98% of all explained variation in the Italy Polaris model (A). The number of treated patients explained the majority of the variability in the PITER model. More than 89% of the variability in the 2030 forecasted viraemic infections could be explained by the estimated number of treated patients. The other drivers of uncertainty in the PITER adjusted model are similar to Italy Polaris model (B)