This article is a summary of a two-part study– “Comparison of Pharmacist-Led Trough vs AUC-Guided Vancomycin Dosing and Monitoring in Adult Patients: Implementation at a Community Hospital” by Hamna Imtiaz*, PharmD, who is a PGY-1 pharmacy resident of Rush Copley Medical Center during the time of the study from May 2023 to July 2023.
* PrecisePK has obtained permission from Dr. Imtiaz to share the results of her study. Please reference this work properly if you wish to use any of the following content for educational or research purposes.
Introduction
This study aims to compare tough-based vancomycin dosing to that of the AUC-based methods at a pharmacist-led institution with a focus on the adult population. The learning objective of Dr. Imitiaz’s study is to review the 2020 vancomycin AUC monitoring guideline recommendations for specific indications and describe outcomes associated with using AUC v.s. trough monitoring.
Background
- 2020 Vancomycin AUC Dosing Guidelines Recap–
- This guideline has addressed dosing recommendations in:
- Morbid obesity
- Pediatrics
- Renal replacement therapies
- There were minimal to no data on the safety and efficacy of targeted trough concentrations of 15 to 20 mg/L.
- AUC/MIC monitoring is recommended for serious MRSA infections including bacteremia, sepsis, endocarditis, osteomyelitis, pneumonia, and meningitis
- Vancomycin AUC/MIC Monitoring Calculations
- Previous Studies on Vancomycin and nephrotoxicity
Preliminary Study
Study Objective
Primary:
- Incidence of nephrotoxicity between the pre- vs. post-implementation groups
- AKI is defined as a serum creatinine (SCr) concentration increase of at least 0.5 mg/dL from baseline or 50% increase from baseline while on vancomycin therapy
Secondary:
- Loading dose of vancomycin in milligrams (mg)
- Inpatient vancomycin therapy exposure in days
- Attainment of target therapeutic drug monitoring (TDM), is defined as the following:
- Target trough of 10-20 mg/L from Jan. 1, 2022 to Mar. 31, 2022
- Target trough of 10-17 mg/L from April 1, 2022 to present
- Target AUC of 400-600 mg*h/L from April 10, 2023 to present
Method
- Pre (AUC-based dosing) implementation Group (n=50)
The pre-implementation group included patients in whom trough-based monitoring was used, aka our current nomogram.
- Post (AUC-based dosing) implementation Group (n=22)
The post-implementation group included patients in which AUC-based monitoring was used with a third-party Bayesian dosing software known as PrecisePK. Below is a screenshot of what the program’s interface looks like.
Intervention
Initial Meeting with PrecisePK → PrecisePK Training & Competency Assessment completed → Vancomycin AUC Dosing Guidance Document
Study Eligibility
This study included adults of 18 years and older. These patients received vancomycin for at least 48 hours for a documented or suspected infection from January 1st, 2022 to the present.
The study excluded patients of the following criteria:
- Pregnant patients
- Received vancomycin for < 48 hours
- Allergy to vancomycin
- Renal transplant patients
- Patients requiring renal replacement therapy or hemodialysis at baseline or within 72 hours of vancomycin initiation
AUC Calculations Using PrecisePK*
Method
Primary Conclusion
The interim analysis supports AUC dosing and monitoring using PPK as potentially lowering nephrotoxicity. Although the final analysis will provide more definitive differences, there has been an overall decrease in the percentage of AKI in the post-implementation group thus far. Out of the 24 appropriately drawn troughs in the pre-implementation group, only 15 were within the TDM target range, Whereas all the AUCs calculated by PPK were within range in the post-implementation group thus far
Conclusion
PrecisePK Cost-Benefit Analysis
Not all institutions have adopted using AUC-based dosing due to the limitations of using a third-party vendor– one of them being cost. This study was able to work with PrecisePK’s team to utilize a free trial for the duration of the project. PrecisePK had the option to be integrated into the hospital’s Epic interface.
According to previous studies that have been done using PrecisePK’s Bayesian Model-Informed Precision Dosing (MIPD), there are significant reductions in costs surrounding malpractice claims and preventable ADEs per patient.
See more of how PrecisePK helps you achieve cost-benefit: https://www.precisepk.com/roi
Study’s Limitations
This study was conducted at a single center and a retrospective study. Loading dose variability is present. The AUC-based dosing protocol was delayed implementation at the study site.
About Rush Copley Medical Center
RUSH Copley Medical Center, a hospital in Aurora, Illinois, has provided quality health care to the residents of greater Fox Valley for more than 130 years. The 210-bed hospital has 500 physicians on staff in more than 60 specialties. It is a destination for excellence in health care with an academic connection to the RUSH University System for Health.
