Background Ventilator-associated pneumonia (VAP) has high impact on costs and resources at hospitals worldwide. Correct antibiotic use could reduce mortality and decrease length of stays. Acquisition cost of doripenem is higher than imipenem but has better health outcomes.

Purpose A cost-effectiveness analysis of doripenem versus imipenem in empiric treatment of VAP.

Materials and methods A simulated decision tree for cost-effectiveness analysis was performed It took into account rescue antibiotic therapy and all end results, include mortality and drug adverse reactions. The authors considered separately the main seven microorganisms causing VAP in our country and the rest were considered together. Population studied consisted of 10,000 simulated patients in Intensive Care Unit with empirical treatment for VAP (64 outcomes each one). The analysis used the hospital perspective and a time horizon lesser than a year. Probabilities of event and VAP aetiology were extracted from clinical trials and database respectively. Costs (€ 2011) included the antibiotic options (Doribax® and Generic imipenem), rescue treatment, length of stay, administration supplies and personnel costs, and DRG (diagnosis-related groups) cost for each event. Different scenarios were tested in deterministic and stochastic sensibility analysis.

Results In deterministic analysis, ICER for 10,000 patient was –12,755.63 €/patient survived. Total cost were 8,693.03 €/patient and 9,063.59 €/patient for doripenem and imipenem respectively. Patient survived in each group were 9,711.14 for doripenem and 9,420.63 for imipenem. Univariable sensibility analysis had almost always the same result as the base model. However in the two scenarios it was up to threshold (20,000€): imipenem had similar length of stay than doripenem and when considered methicillin-sensitivity Staphylococcus aureus as single microorganism causing the infection. Probabilistic sensibility analysis, 2,000 Monte-Carlo simulations, showed an RCEI of – 391,762.10 (SD: 350,012.96) €/patient survived. Up than 80% simulations, imipenem was dominated.

Conclusions Doripenem is a better cost-effectiveness option than imipenem for VAP empirical treatment.