Comparison of Vancomycin Area-Under-the-Curve Dosing Versus Trough Target–Based Dosing in Obese and Nonobese Patients With Methicillin-Resistant <i>Staphylococcus aureus</i> Bacteremia

Abstract

<b>Background:</b> A vancomycin target of area under the curve to minimum inhibitory concentration (AUC:MIC) ratio ≥400 is recommended for treatment of methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) bacteremia. <b>Objective:</b> To evaluate vancomycin total daily dose (TDD) achieving trough targets versus a calculated strategy achieving AUC targets based on body mass index (BMI). <b>Methods:</b> A retrospective cohort study was performed within a large hospital network. Patients with MRSA bacteremia were eligible if they received vancomycin with a steady-state trough (15-20 mg/L). Cockcroft-Gault was used to estimate creatinine clearance, calculating vancomycin clearance and AUC. Patients were stratified by BMI (less than/greater than 30 kg/m²). The primary outcome was vancomycin TDD for the trough-based strategy compared with an AUC-dosing strategy. <b>Results:</b> A total of 119 patients were included, including 51 (42.9%) and 68 (57.1%) patients with high- and low-BMI, respectively. The TDD for trough-based dosing (2390.76 ± 1224.59 mg) differed significantly from AUC-based dosing (1985.07 ± 616.18 mg) across the cohort (<i>P</i> = 0.0014). For patients with high BMI, there was a significant difference (<i>P</i> < 0.0001) in TDD between trough (2637.25 ± 1327.89 mg) versus AUC (1918.71 ± 625.89 mg) strategies. No difference in TDD between dosing strategies was observed among low-BMI patients. Across all patients, 46 (38.7%) experienced acute kidney injury (AKI); high-BMI patients experienced higher rates of AKI compared with low-BMI patients (54.9 vs 26.5%; <i>P</i> = 0.002). <b>Conclusions and Relevance:</b> An AUC-based dosing strategy may reduce vancomycin TDD required for MRSA bacteremia compared with trough-based dosing, particularly for patients with higher BMI.