Cost-effectiveness analysis of an antimicrobial stewardship team on bloodstream infections: a probabilistic analysis

We sought to determine the cost-effectiveness of Antimicrobial Stewardship Teams (ASTs) on the reduction of morbidity and mortality associated with nosocomial bacteraemia. A decision analytic model compared costs and outcomes of bacteraemic patients receiving standard treatment with or without an AST consult. Patients with a bacteraemic event during their hospital admission were included in the model. Effectiveness was estimated as quality-adjusted life years (QALYs) over the lifetime of patients. Model variables and costs, along with their distributions, were obtained from the literature and expert opinion. Incremental cost-effectiveness ratios (ICERs) were calculated to estimate the cost per QALY gained from the hospital perspective. Uncertainty in ICERs was evaluated with probabilistic sensitivity analyses. The cost-effectiveness of clinical decision support systems was evaluated as a secondary analysis. Implementing an AST for bacteraemia review cost $39 737 (95% CI $27 272-53 017) and standard treatment cost $39 563 (95% CI $27 164-52 797). The difference in effectiveness between the two strategies was 0.08 QALYs, and the base case ICER from the probabilistic analysis was $2367 per QALY gained [95% CI dominant (less costly, more effective) to $24 379]. Results from the probabilistic sensitivity analysis demonstrated there was more than a 90% likelihood that an AST would be cost-effective at a level of $10 000 per QALY. Maintaining an AST to improve care for bacteraemia is cost-effective from the hospital perspective. The estimate of $2367 per QALY gained for the AST intervention compares favourably with many currently funded healthcare interventions and services.