Comparison of Trough-Only and Peak–Trough Concentration Data for the Calculation of Vancomycin Area under the Concentration–Time Curve on Day 1 or Day 2

Area under the concentration-time curve (AUC)-guided vancomycin dosing is recommended to measure peak and trough concentrations. While recent studies have shown that AUC on Day 1 and Day 2 are associated with early clinical response and nephrotoxicity, data confirming the accuracy of AUC estimation using trough-only data on Day 1 and Day 2 are scarce. The aim of this study was to evaluate the agreement of AUC calculated using trough-only data compared with 2-point sampling on Day 1 and Day 2 using the Bayesian-based, free web application PAT (Practical AUC-guided TDM for vancomycin). We conducted a single-center, cohort study to evaluate the agreement of AUC calculated using trough-only data compared to peak-trough sampling on Day 1 and Day 2. The ratios of trough/peak-trough AUC for AUC_0-24 and AUC_24-48 were within the acceptable range of 0.8-1.2. Furthermore, AUCs estimated using trough-only data and those estimated using peak-trough concentrations showed high agreement. In addition, multivariate ordinal logistic regression analysis showed that estimated glomerular filtration rate and serum albumin were significant factors affecting the deviation of trough/peak-trough AUC_24-48 (p = 0.001 and p = 0.040, respectively). In conclusion, trough-only data may be sufficient for AUC estimation in AUC-guided dosing in patients identified as suitable candidates, even when obtained on Day 2. Further, renal function and serum albumin were found to be factors affecting the agreement rate of AUC on Day 2 when using trough-only data.