Comparative cost-effectiveness of alternative empiric antimicrobial treatment options for suspected enterococcal...

Enterococcus species are the fourth leading cause of bacteremia. Resistance rates are rising and delays in appropriate initial antimicrobial therapy have been associated with increased mortality. Empiric treatment of patients with suspected enterococcal bacteremia varies and significant cost differences exist between alternatives. The objective of this study was to determine the cost-effectiveness of various empiric treatments for patients with suspected enterococcal bacteremia.

A decision-analytic model was constructed from the hospital perspective to assess the cost-effectiveness of alternative empiric treatment options for enterococcal bacteremia, including antimicrobials active against vancomycin-resistant enterococcus (VRE). The model was populated from available literature sources and included resistance patterns, associated mortality with early versus delayed effective treatment, and the cost of treatment. Univariate sensitivity analyses tested the robustness of the model to determine the degree to which model uncertainties influenced outcomes. We also undertook a probabilistic sensitivity analysis varying parameters in 10,000 Monte Carlo simulations.

The incremental cost-effectiveness ratio was $791 and $749/quality-adjusted-life-year utilizing empiric daptomycin and linezolid, respectively. The model also predicted an incremental cost/life saved of $11,703 by utilizing empiric daptomycin and $11,084 with linezolid utilization. Ampicillin was dominated (i.e., less effective and associated with increased costs) by both VRE-active agents and vancomycin. A probabilistic Monte Carlo sensitivity analysis showed that an agent with VRE activity had a 100% chance of being cost-effective at traditionally used willingness-to-pay thresholds. The decision-analytic model was sensitive to variations in E. faecium mortality and short-term postdischarge survival rates.

Results of our model showed that empiric utilization of an antimicrobial with activity against VRE may be a cost-effective option for the treatment of suspected enterococcal bacteremia when compared with vancomycin or β-lactam therapy.