Cost-effectiveness model of empiric doripenem compared with imipenem-cilastatin in ventilator-associated pneumonia
Marya D Zilberberg1, Samir H Mody, Joyce Chen
1School of Public Health and Health Sciences, University of Massachusetts, Amherst, MA, USA. Marya@evimedgroup.org
Background:
Ventilator-associated pneumonia (VAP) is a common complication of critical illness among surgical and trauma patients. Inappropriate empiric treatment of VAP increases the mortality rate. The rates of Pseudomonas aeruginosa (PA) VAP susceptibility to doripenem (DOR) are higher than those to imipenem-cilastatin (IMI). We developed a model to quantify outcome differences between strategies of empiric treatment of VAP with DOR vs. IMI.
Methods:
We designed a cost-effectiveness model comparing empiric treatment of VAP with DOR vs. IMI from both the hospital and societal perspectives. We examined the differences in the number of deaths, hospital length of stay (LOS), total costs, and quality-adjusted life years (QALY) under each scenario and conducted Monte Carlo simulations and sensitivity analyses to determine the stability of our estimates. Drug costs were taken as 80% of wholesale acquisition costs, with other inputs derived from the literature.
Results:
In the base case analysis, assuming a PA-VAP attributable mortality rate of 38.4% and a 49% relative risk reduction in deaths in PA-sensitive (PA-S) infections to empiric drug compared with a resistant PA (PA-R) organism, DOR use resulted in three additional deaths avoided, 117.4 days of hospitalization averted, and hospital savings of $422,524 per 1,000 patients treated at a cost of $5,748/QALY. All estimates were most sensitive to the costs of treating PA-S and PA-R infections. In a multivariable analysis, hospital cost savings persisted across >80% of the simulations (95% confidence interval $432,615-$2,148,540).
Conclusions:
Given the current microbiologic sensitivity profile of PA to DOR and IMI, and depending on the local susceptibility patterns and in institutions where DOR in vitro susceptibilities are superior to those of other carbapenems for PA clinical isolates, empiric treatment of VAP with DOR may dominate that with IMI by being both life- and cost-saving.
Insights
Doripenem (DOR) may be a more cost-effective treatment for ventilator-associated pneumonia (VAP) caused by Pseudomonas aeruginosa (PA) than imipenem-cilastatin (IMI). DOR use can reduce deaths, hospital stays, and costs, especially when PA is susceptible to it.
Area of Science:
- Critical Care Medicine
- Infectious Diseases
- Health Economics
Background:
- Ventilator-associated pneumonia (VAP) is a significant complication in critically ill surgical and trauma patients.
- Inappropriate empiric treatment of VAP elevates mortality rates.
- Pseudomonas aeruginosa (PA) exhibits higher susceptibility to doripenem (DOR) than imipenem-cilastatin (IMI).
Purpose of the Study:
- To develop a model quantifying outcome differences between empiric VAP treatment strategies using DOR versus IMI.
- To assess the cost-effectiveness of DOR compared to IMI for VAP management.
Main Methods:
- A cost-effectiveness model was designed comparing DOR and IMI for empiric VAP treatment.
- Analyses included deaths, hospital length of stay (LOS), total costs, and quality-adjusted life years (QALY).
- Monte Carlo simulations and sensitivity analyses were performed; drug costs were 80% of wholesale acquisition costs.
Main Results:
- Doripenem (DOR) use averted 3 deaths, 117.4 hospital days, and saved $422,524 per 1,000 patients.
- The cost per QALY gained with DOR was $5,748.
- Hospital cost savings with DOR persisted in over 80% of simulations, ranging from $432,615 to $2,148,540.
Conclusions:
- Empiric VAP treatment with DOR may be superior to IMI, offering both life-saving and cost-saving benefits.
- The advantage of DOR is contingent on local PA susceptibility patterns and its in vitro superiority over other carbapenems.
- Doripenem demonstrates potential to dominate IMI in VAP treatment based on current susceptibility profiles.
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