The aim of this study was to assess the cost-effectiveness of linezolid (LIN) versus vancomycin (VAN) for the treatment of ventilator-associated pneumonia (VAP) using a decision model analysis from the National Health System perspective. Patients and participants comprising four subgroups were analyzed: all, Gram-positive (GP), Staphylococcus aureus (SA), methicillin-resistant SA (MRSA). The treatments were LIN 600 mg i.v., every 12 hours, 10 days and VAN 1,000 mg i.v., every 12 hours 10 days. The primary outcome was the incremental cost-effectiveness of LIN in terms of cost per added quality-adjusted life year (QALY) gained. The secondary outcome was the marginal cost per year of life saved (LYS) generated by using LIN. Clinical cure and survival rates estimates were derived from a retrospective analysis of two trials comparing LIN with VAN. QALY was based on time-trade off study. Resource use and unit costs (Euros 2003) were obtained from Spanish VAP treatment and health cost databases. The additional QALY and LYS per LIN patients were 0.392; 0.688; 0.606; 1.805 and 0.471; 0.829; 0.729; 2.175 respectively, compared with those of VAN in the patients with VAP (all, GP, SA, and MRSA, respectively). The additional costs for LYS with LIN, as compared to VAN were 1,501.31; 827.63; 955.13 and 289.51 Euros, respectively. The additional cost per QALY with LIN was 1,803.87; 997.25; 1,149.00 and 348.85 Euros, respectively.
Conclusions: LIN was more cost-effective than VAN in the treatment of VAP in Spain, with an additional cost per QALY/LYS gained below the acceptable threshold in Spain of Euros 30,000 for new therapies.