Cost-effectiveness of screening the US blood supply for Trypanosoma cruzi

Abstract

Background: Trypanosoma cruzi, the etiologic agent of Chagas disease, is a potential threat to transfusion recipients in the United States. The cost-effectiveness of seven testing strategies was evaluated against no testing and hierarchically in incremental analysis. Donor-specific strategies included testing donors born in endemic countries, testing all donors a specific number of times, or testing all donors every time. Component-specific strategies are based on screening platelet-containing donations.

Study design and methods: A decision analytic model simulated the lifetime cost (US dollars) and health outcomes (quality-adjusted life-years [QALYs]) of two hypothetical cohorts of blood recipients, an all-ages and a younger subset, from a 2007 societal perspective. Model variable values were obtained from US screening data, Blood Systems Laboratory, the Health Care Utilization Project, and published literature.

Results: For the all-ages cohort, compared to no testing, the cost-effectiveness of testing all donors one time was $757,000 per QALY, all donors two times $970,000 per QALY, and universal testing $1.36 million per QALY. In the all-ages and the younger transfused populations, testing donors with geographical exposure was most cost-effective ($173,000 and $29,000/QALY, respectively). The most influential variables in the model were related to characteristics of the transfused population: survival and health state utilities. With respect to T. cruzi variables, results were most sensitive to seroprevalence and transmissibility.

Conclusion: Selective T. cruzi screening generates nearly the same effectiveness as universal screening, but at a reduced cost. Outcomes and associated costs of Chagas disease take longer to materialize than the average life expectancy of transfusion recipients.