Linezolid Versus Vancomycin in the Empiric Treatment of Nosocomial Pneumonia: A Cost-Utility Analysis Incorporating Results from the ZEPHyR Trial.

OBJECTIVE: To examine the cost-effectiveness of vancomycin versus linezolid in the empiric treatment of nosocomial pneumonias incorporating results from a recent prospective, double-blind, multicenter, controlled trial in adults with suspected methicillin-resistant Staphylococcus aureus (MRSA) nosocomial pneumonia. METHODS: A decision-analytic model examining the cost-effectiveness of linezolid versus vancomycin for the empiric treatment of nosocomial pneumonia was created. Publicly available cost, efficacy, and utility data populated relevant model variables. A probabilistic sensitivity analysis varied parameters in 10,000 Monte-Carlo simulations, and univariate sensitivity analyses assessed the impact of model uncertainties and the robustness of our conclusions. RESULTS: Results indicated that the cost per quality-adjusted life-year (QALY) increased 6% ($22,594 vs. $23,860) by using linezolid versus vancomycin for nosocomial pneumonia. The incremental cost per QALY gained by using linezolid over vancomycin was $6,089, and the incremental cost per life saved was $68,615 with the use of linezolid. Vancomycin dominated linezolid in the subset of patients with documented MRSA. The incremental cost per QALY gained using linezolid if no mortality benefit exists between agents or a 60-day time horizon was analyzed was $19,608,688 and $443,662, respectively. CONCLUSIONS: Linezolid may be a cost-effective alternative to vancomycin in the empiric treatment of patients with suspected MRSA nosocomial pneumonia; however, results of our model were highly variable on a number of important variables and assumptions including mortality differences and time frame analyzed.

Impact of different antimicrobial therapies on clinical and fiscal outcomes of patients with bacteremia due to vancomycin-resistant enterococci.

Vancomycin-resistant enterococci (VRE) are a growing health problem, and uncertainties exist regarding the optimal therapy for bloodstream infection due to VRE. We conducted systematic comparative evaluations of the impact of different antimicrobial therapies on the outcomes of patients with bloodstream infections due to VRE. A retrospective study from January 2008 to October 2010 was conducted at Detroit Medical Center. Unique patients with blood cultures due to VRE were included and reviewed. Three major therapeutic classes were analyzed: daptomycin, linezolid, and ß-lactams. Three multivariate models were conducted for each outcome, matching for a propensity score predicting the likelihood of receipt of one of the therapeutic classes. A total of 225 cases of bacteremia due to VRE were included, including 86 (38.2%) cases of VR Enterococcus faecalis and 139 (61.8%) of VR Enterococcus faecium. Bacteremia due to VR E. faecalis was more frequent among subjects treated with ß-lactams than among those treated with daptomycin or linezolid. The median dose of daptomycin was 6 mg/kg of body weight (range, 6 to 12 mg/kg). After controlling for propensity score and bacteremia due to VR E. faecalis, differences in mortality were nonsignificant among the treatment groups. Therapy with daptomycin was associated with higher median variable direct cost per day than that for linezolid. This large study revealed the three therapeutic classes (daptomycin, linezolid, and ß-lactams) are similarly efficacious in the treatment of bacteremia due to susceptible strains of VRE.