Modeling the economic impact of linezolid versus vancomycin in confirmed nosocomial pneumonia caused by methicillin-resistant Staphylococcus aureus (Critical Care)

IntroductionThe economic impacts of linezolid and vancomycin were compared for the treatment of hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA)-confirmed nosocomial pneumonia. Methods: A 4-week decision tree model incorporated published data and expert opinion on clinical parameters, resource use, and costs (2012 US dollars), such as efficacy, mortality, serious adverse events, treatment duration, and length of stay. Results are presented from a US payer perspective. The base case first-line treatment duration for patients with MRSA-confirmed nosocomial pneumonia was 10 days. Clinical treatment success (used for cost effectiveness ratio) and failure due to lack of efficacy, serious adverse events, or mortality were possible clinical outcomes that could impact costs. Cost of treatment and incremental cost effectiveness per successfully treated patient were calculated for linezolid vs. vancomycin. Univariate (one-way) and probabilistic sensitivity analysis were conducted. Results: The model calculated total base case inpatient costs of $46,168 (linezolid) and $46,992 (vancomycin). The incremental cost effectiveness ratio favored linezolid (vs. vancomycin), with lower costs ($824 less) and greater efficacy (+2.7% absolute difference in the proportion of patients successfully treated for MRSA nosocomial pneumonia). Approximately 80% of the total treatment costs were attributed to hospital stay (primarily in the intensive care unit). Probabilistic sensitivity analysis indicated linezolid as the cost-effective alternative under varying willingness to pay thresholds. Conclusion: The model results showed that linezolid has a favorable incremental cost effectiveness ratio compared to vancomycin for MRSA-confirmed nosocomial pneumonia, largely attributable to the higher clinical trial response rate of patients treated with linezolid. The higher drug acquisition cost of linezolid was offset by lower treatment failure-related costs and fewer days of hospitalization.