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

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.

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.

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.

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.