Clinical Relevance of a Vancomycin 24 h Area under the Concentration—Time Curve Values Using Different Renal Function Equations in Bayesian Dosing Software

With the updated 2020 vancomycin therapeutic drug monitoring (TDM) guidelines suggesting a ratio of area under the curve over 24 h to a minimum inhibitory concentration (AUC(24)/MIC) as a target from the Infectious Diseases Society of America, an accurate estimation of AUC(24) has become more critical. We aim to compare the AUC(24) using Bayesian dosing software according to various estimated glomerular filtration rate (eGFR) equations in order to analyze the clinical impact of eGFR in vancomycin TDM. We reviewed the TDM dataset of 214 adult patients and analyzed the AUC(24) values from various renal function equations, including the Cockcroft-Gault (C-G), the modification of diet in renal disease (MDRD), the chronic kidney disease epidemiology collaboration (CKD-EPI), and the revised Lund–Malmö. The AUC(24)/MIC results (assuming a MIC of 1 mg/L) were divided into three groups as follows: <400, 400–600, and >600. Additionally, we compared the group agreement between the C-G and the three eGFR formulas. Although there was a statistically significant difference in the AUC24 of the MDRD and the CKD-EPI formulas compared to the C-G, the group concordance rate of the eGFR formula was 95.2–100%, which indicates no clinical significance. The clinical impact of the eGFR formula type on drug dosing recommendations in vancomycin TDM using Bayesian software was insignificant in clinical practice.