Assessing the Use of a Single Vancomycin Level in Predicting Area Under the Curve: A Retrospective Analysis in a Veteran Affairs Population

Faculty Mentor

Jaclyn Cusumano

Major/Area of Research

Pharmacy - Infectious Disease

Description

INTRODUCTION: Current vancomycin guidelines recommend monitoring area under the curve (AUC; target 400-600mg*h/L) to optimize efficacy and minimize toxicity. Historically, guidelines suggested monitoring with trough concentrations (15-20 mg /L) as a surrogate marker for AUC but were found to be associated with nephrotoxicity. Due to challenges in AUC monitoring, several centers continue to use trough monitoring. We sought to determine if a single vancomycin concentration can accurately predict an AUC of 400-600mg*h/L.

METHOD: Patients on vancomycin with a subsequent vancomycin level at the James J. Peter’s Department of Veterans Affairs Medical Center between January 1, 2023 and December 31, 2023, were retrospectively reviewed. Patient’s undergoing renal replacement therapy (RRT) were excluded. We collected patient age, race, height (inches), weight(kg), ethnicity, patient location, admission/discharge date, renal function, days of therapy (DOT), vancomycin dose, total daily dose, infusion time, and corresponding vancomycin level that was collected. Utilizing previously defined pharmacokinetic equations from an online calculator, AUC was predicted based on the single trough concentrations collected. The AUC was correlated to single concentrations using Spearman’s rank correlation.

RESULTS: A total of 34 patients met the inclusion criteria, and 116 vancomycin levels were assessed. The median vancomycin trough level was 15.8 mg/L (interquartile range [IQR], 11.47- 18.97), Vd= 58.82 L, Cl= 3.16 L/hr (IQR, 1.89- 4.40), and true trough of 13.89 mg/L (IQR, 7.93- 18.81). The median calculated elimination rate constant (ke) was 0.05 hr-1 (IQR 0.03-0.07). The median estimated AUC= 525.87mg*h/L (IQR, 351.96- 654.64). The Pearson coefficient is r= 0.7977415, showing the correlation between the trough and AUC.

CONCLUSION: There is a strong positive correlation between the vancomycin concentration levels obtained and predicting AUC.

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Assessing the Use of a Single Vancomycin Level in Predicting Area Under the Curve: A Retrospective Analysis in a Veteran Affairs Population

INTRODUCTION: Current vancomycin guidelines recommend monitoring area under the curve (AUC; target 400-600mg*h/L) to optimize efficacy and minimize toxicity. Historically, guidelines suggested monitoring with trough concentrations (15-20 mg /L) as a surrogate marker for AUC but were found to be associated with nephrotoxicity. Due to challenges in AUC monitoring, several centers continue to use trough monitoring. We sought to determine if a single vancomycin concentration can accurately predict an AUC of 400-600mg*h/L.

METHOD: Patients on vancomycin with a subsequent vancomycin level at the James J. Peter’s Department of Veterans Affairs Medical Center between January 1, 2023 and December 31, 2023, were retrospectively reviewed. Patient’s undergoing renal replacement therapy (RRT) were excluded. We collected patient age, race, height (inches), weight(kg), ethnicity, patient location, admission/discharge date, renal function, days of therapy (DOT), vancomycin dose, total daily dose, infusion time, and corresponding vancomycin level that was collected. Utilizing previously defined pharmacokinetic equations from an online calculator, AUC was predicted based on the single trough concentrations collected. The AUC was correlated to single concentrations using Spearman’s rank correlation.

RESULTS: A total of 34 patients met the inclusion criteria, and 116 vancomycin levels were assessed. The median vancomycin trough level was 15.8 mg/L (interquartile range [IQR], 11.47- 18.97), Vd= 58.82 L, Cl= 3.16 L/hr (IQR, 1.89- 4.40), and true trough of 13.89 mg/L (IQR, 7.93- 18.81). The median calculated elimination rate constant (ke) was 0.05 hr-1 (IQR 0.03-0.07). The median estimated AUC= 525.87mg*h/L (IQR, 351.96- 654.64). The Pearson coefficient is r= 0.7977415, showing the correlation between the trough and AUC.

CONCLUSION: There is a strong positive correlation between the vancomycin concentration levels obtained and predicting AUC.