Analysis of Risk Factors Affecting Vancomycin Low Trough Concentrations for Emergency and Critically Ill Patients

Abstract

In the administration of vancomycin (VCM) for emergency and critically ill patients, insufficient VCM trough concentrations were occasionally observed. We performed this study to identify independent risk factors related to VCM low trough concentrations (< 10 µg/mL) for emergency and critically ill patients. Forty-six patients treated with VCM based on therapeutic drug monitoring guidelines between January 2013 and December 2015 were enrolled. Risk factors associated with VCM low trough concentrations were examined by comparing various factors of patients. Multiple regression analysis showed that the initial trough concentrations of VCM were related to age, body weight, estimated glomerular filtration ratio (eGFR (mL/min/1.73m²)), presence of trauma, average urine volume, and daily dose of VCM. Additionally logistic regression analysis identified eGFR (adjusted odds ratio = 1.044, 95％ confidence interval = 1.005 - 1.085, P = 0.028), average urine volume (adjusted odds ratio = 1.066, 95％ confidence interval = 1.018 - 1.116, P = 0.007), and daily dose of VCM (adjusted odds ratio = 0.873, 95％ confidence interval = 0.764 - 0.998, P = 0.046) as being an independent risk factor associated with VCM low trough concentrations. Therefore, determining the daily dose of VCM in consideration of the eGFR and the average urine volume may prevent VCM low trough concentrations. Also, it is important to actively monitor since two factors change over time.