The association of elevated trough serum vancomycin concentrations with obesity

BackgroundObese patients display differences in vancomycin drug disposition, which may complicate attainment of appropriate serum vancomycin concentrations (SVCs). This study was conducted to determine if obesity leads to trough SVCs above the therapeutic range.MethodsThis retrospective cohort study sought to determine the rate and predictors of high (i.e. >20 mg/L) serum trough levels according to level of obesity.ResultsIncreasing BMI predicted SVCs > 20 mg/L after controlling for dose, age, and serum creatinine. Obese patients had significantly higher mean trough SVCs compared to non-obese patients (16.5 mg/L vs 12.1 mg/L, p = 0.004) and a significantly higher proportion of obese patients had trough SVCs > 20 mg/L (18.9% vs 4.2%, p = 0.03).ConclusionIncreasing obesity predicted higher probabilities of SVCs > 20 mg/L. Development of alternative dosing and management strategies for vancomycin may be necessary to account for pharmacokinetic changes associated with obesity.