Cost-minimization in Health: Linezolid versus vancomycin with serum monitoring in patients with incipient renal failure – a simulation and real-life / Minimização de custos em Saúde: Linezolida versus vancomicina com monitoramento sérico em pacientes com insuficiência renal incipiente - uma simulação e vida real

Vancomycin serum levels (VSL) were measured to prevent dose-dependent side effects. However, the cost of VSL is high, therefore in some cases alternative antibacterial treatments, such as linezolid, can be used. The aim of this study was to perform an economic analysis of the cost of linezolid compared to vancomycin plus therapeutic drug monitoring. This is an ecological, retrospective, quantitative study, conducted in a Brazilian public university hospital. The study period was from January 2018 to January 2019. First part from January/18 - July/18 based on pre-linezolid data (T1) and another after the introduction of linezolid from August/18 - January/19 (T2). A breakeven analysis to vancomycin substitution was performed following 3 scenarios: (i) in all patients, (ii) in critically ill patients with renal failure or (iii) only in patients in hemodialysis. The DDD/1000-patients day, MRSA incidence, costs with VSL, as well as the costs of drugs (vancomycin and linezolid) and infusion kits were evaluated. Vancomycin was substituted in critically ill patients with renal failure from T1 to T2. The incidence of MRSA infections did not vary between T1 and T2. Vancomycin consume maintained constant (p=0.157); while linezolid consuming increased (0 DDD/1000PD versus 33.4 DDD/1000PD; p=0.002). Vancomycin and linezolid costs was lower in T1 than T2 (USD 9202,00 versus 11331,00; p=0.015). Linezolid implementation as a strategy to avoid vancomycin plus VSL was not cost-effective in critically ill patients with renal failure. More studies are needed to understand if linezolid implementation may be cost-effective in different scenarios.