Attributable nephrotoxicity of vancomycin in critically ill patients: a marginal structural model study

Area of Science:

• Critical care medicine
• Nephrology
• Pharmacology

Background:

• Determining vancomycin's specific contribution to acute kidney injury (AKI) in critically ill patients is challenging due to multiple potential causes.
• Existing data may overestimate vancomycin-induced nephrotoxicity in this vulnerable population.

Purpose of the Study:

• To quantify the risk of AKI attributable to vancomycin in critically ill patients.
• To identify specific vancomycin exposure parameters associated with AKI and severe AKI.

Main Methods:

• Utilized a large public database to extract time-fixed and time-varying variables for 26,865 patients.
• Analyzed vancomycin exposure, serum trough levels (>15 and >20 mg/L), and combination therapy with piperacillin/tazobactam.
• Employed inverse probability of treatment weighting and marginal structural models to assess AKI, severe AKI, and renal replacement therapy (RRT) need.

Main Results:

• Vancomycin exposure was associated with an increased risk of AKI (HR=1.24) but not severe AKI or RRT.
• Vancomycin trough levels >20 mg/L significantly increased the risk of AKI (HR=1.90) and severe AKI (HR=1.69).
• Concomitant vancomycin and piperacillin/tazobactam did not elevate AKI risk compared to vancomycin alone.

Conclusions:

• The attributable nephrotoxicity of vancomycin in critically ill patients is lower than previously suggested.
• Severe AKI is primarily associated with vancomycin when serum trough levels consistently exceed 20 mg/L.
• Current guidelines for vancomycin dosing and monitoring in critically ill patients may need refinement.