1415. Implementation and Validation of a Vancomycin AUC/MIC Calculator and Dosing Protocol at a Large Community Hospital

BACKGROUND: Current IDSA guidelines recommend targeting a vancomycin trough between 15 and 20 mg/L to achieve an AUC/MIC ≥ 400; however, recent literature shows increased rates of nephrotoxicity within this range and the target AUC/MIC ratio may be achieved with lower troughs. We sought to determine whether a vancomycin AUC-based dosing protocol and spreadsheet-based calculator, using one-compartment population-based dosing and two steady-state serum levels, accurately predicted AUC/MIC ratio in patients with moderate to severe Staphylococcus aureus infections. METHODS: A retrospective analysis of 60 adult patients treated with vancomycin for culture-confirmed S. aureus was conducted. The primary outcome was percent of patients who met the AUC/MIC goal of ≥400. Secondary outcomes included: mean initial trough concentration in patients who met the AUC/MIC goal compared with those who did not; correlation of two different methods of AUC-estimation with the patient’s actual AUC; percentage of patients meeting AUC/MIC goal stratified by initial trough concentrations, age, weight, and indication; and percentage of patients meeting the AUC goal stratified by the same variables. Results were analyzed using descriptive statistics and calculations were performed using SPSS. RESULTS: The median age (range) was 55 (22–86) and 52% were male. Eighty-three percent of patients achieved an initial AUC/MIC ≥ 400, including 93% with serum troughs between 10 and 14.9 mg/L. Patients who met the AUC/MIC goal had an average trough of 13.5 mg/L, whereas those who did not had an average trough of 7.8 mg/L (P < 0.001). AUC estimation using population pharmacokinetics was significantly correlated with actual AUC (P = 0.011); however, this was not a strong correlation (r = 0.340). Subgroup analysis based on age, weight, and indication identified areas for improvement in the empiric dosing protocol at our institution. CONCLUSION: Use of the vancomycin AUC-based dosing protocol and calculator resulted in achievement of efficacy goal in the majority of patients, including many with vancomycin troughs between 10 and 15 mg/L. More accurate estimation of AUC and other pharmacokinetic variables using local patient data is important for improving the reliability of vancomycin dosing protocols. [Image: see text] DISCLOSURES: All authors: No reported disclosures.