Area-Under-Curve-Guided Versus Trough-Guided Monitoring of Vancomycin and Its Impact on Nephrotoxicity: A Systematic Review and Meta-Analysis

Therapeutic drug monitoring versus Bayesian AUC-based dosing for vancomycin in routine practice: a cost-benefit analysis

BACKGROUND

AUC-based dosing with validated Bayesian software is recommended as a good approach to guide bedside vancomycin dosing.

OBJECTIVES

To compare treatment and vancomycin-associated acute kidney injury (AKI) costs between Bayesian AUC-based dosing and conventional therapeutic drug monitoring (TDM) using steady-state plasma concentrations of vancomycin administered as continuous infusion in hospitalized non-critically ill patients with severe Gram-positive infection.

METHODS

A cost-benefit analysis presented as a return on investment (ROI) analysis from a hospital perspective was conducted using a decision tree model (TDM versus AUC-based dosing) to simulate treatment cost (personnel, serum sampling and drug cost), vancomycin-associated AKI risk and cost up to 14 days. ROI was calculated against AUC-based software cost. One-way and probabilistic sensitivity analyses (respectively OWSA and PSA) were performed to check for robustness.

RESULTS

In base case, an overall cost per patient of €621.0 with TDM and €543.6 with AUC-based dosing resulted in a treatment saving of €77.4 per patient when applying AUC-based dosing. This saving against the software cost (€26.9/patient) generated an ROI per patient of €1.9 per invested € in software [€1.9 (95% CI 1.6-2.2) in PSA]. Enrolling 900 AUC-based dosed patients annually translated to a net saving of €45 469. Software break-even was reached after 313 patients. In OWSA, a higher AKI risk with TDM strongly contributed to a positive ROI.

CONCLUSIONS

AUC-based dosing appeared a cost-saving strategy compared with conventional TDM when applying base-case settings of vancomycin-associated AKI risk, treatment and AKI costs.

Evaluation of the appropriateness of vancomycin therapeutic drug monitoring in the intensive care unit with a clinical pharmacy approach, a cross-sectional study

OBJECTIVES

Vancomycin, a glycopeptide antibiotic has antibacterial activity against Gram-positive bacteria and is frequently used in the intensive care unit (ICU). Inappropriate therapeutic drug monitoring (TDM) of vancomycin is a common problem encountered in hospital daily practice. The aim of this study was to evaluate the appropriateness of vancomycin trough-guided TDM in patients treated in the ICU using a clinical pharmacy approach.

METHODS

The study was conducted retrospectively in patients over 18 years old who had at least one vancomycin trough level and who had received intravenous (IV) vancomycin for ≥3 days between 1 November 2020 and 1 April 2022. The study included 137 patients. Patient demographics and relevant vancomycin TDM data were collected from medical records. The appropriateness of TDM was evaluated according to the criteria established based on the monitoring recommendations specified in consensus guidelines for therapeutic drug monitoring of vancomycin published by the American Society of Health-System Pharmacists (ASHP) in 2009 and 2020.

RESULTS

Of a total of 238 vancomycin trough levels measured in patients, 32.4% were collected at an inappropriate time. When patients were evaluated in terms of TDM appropriateness according to vancomycin level ranges (<10 µg/mL, 10-20 µg/mL and >20 µg/mL), we found the appropriate TDM was significantly higher in the therapeutic range (10-20 µg/mL) (p <0.001). Of the total 238 vancomycin trough concentrations taken from patients, 77 (32.4%) were measured at an inappropriate time. This caused dose withholding, wrong adjustments and therapy failure. The total TDM appropriateness of vancomycin was significantly higher in the therapeutic range defined as 10-20 µg/mL when evaluated based on 'TDM appropriateness criteria' (p <0.001).

CONCLUSION

Our study shows that appropriate vancomycin TDM increases the likelihood of achieving target trough concentrations. Involvement of clinical pharmacists in TDM management may prevent the development of adverse reactions by ensuring appropriate sampling time and appropriate interpretation of vancomycin levels.

Appropriate use of vancomycin in a cardiac surgical unit

BACKGROUND

Antibiotic resistance is a rapidly growing problem. Methicillin-resistant staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) are major worries, particularly in developing nations where cost-effectiveness is essential. Use of vancomycin must be restricted to prevent resistant to it. Examining the appropriateness rate of vancomycin use in light of the recommendations of the Infectious Disease Society of America (IDSA) in the cardiac surgery ward was the aim of this study.

METHODOLOGY

This study was a retrospective analysis of the medical records of patients who received vancomycin over the previous year, from January 2023 to December 2023. The collected patient data included demographics, indications for vancomycin use, culture and sensitivity test results, concurrent antibiotic medications, vancomycin serum levels, and diagnoses. The appropriateness of vancomycin use was classified according to the recommendations of the Infectious Diseases Society of America (IDSA).

RESULTS

A total of 294 patients received vancomycin. The appropriate use of vancomycin was significantly higher than its inappropriate use (p = 0.001). Approximately 41% (n = 120) of patients were administered vancomycin for treatment purposes, while the remainder received it empirically, but not as surgical prophylaxis. Appropriate use of vancomycin was observed in 89.1% (n = 262) of patients. However, there remained a notable rate of inappropriate vancomycin use (n = 32, 10.9%). The most common reason for inappropriate use was the continuation of vancomycin beyond 72 h without further evidence of a Gram-positive infection (n = 21, accounting for 65.6% of all inappropriate use).

CONCLUSIONS

The current study demonstrated that 89.1% of vancomycin use was appropriate, while approximately 10% was inappropriate, potentially contributing to vancomycin resistance. The majority of inappropriate use stems from frequent empirical prescribing, which requires further review and monitoring.

Switching Vancomycin Monitoring From Trough Concentration to Area Under the Curve Estimation by Bayesian Forecasting: A Short Communication on a Cost-Benefit Study in Resource-Limited Settings

BACKGROUND

This study was conducted to evaluate the cost-benefit indicators of a vancomycin monitoring protocol based on area under the curve estimation using commercial Bayesian software.

METHODS

This quasi-experimental study included patients who were aged >18 years with a vancomycin prescription for >24 hours. Patients who were terminally ill or those with acute kidney injury (AKI) ≤24 hours were excluded. During the preintervention period, doses were adjusted based on the trough concentration target of 15-20 mg/L, whereas the postintervention period target was 400-500 mg × h/L for the area under the curve. The medical team was responsible for deciding to stop the antimicrobial prescription without influence from the therapeutic drug monitoring team. The main outcomes were the incidence of AKI and length of stay. Cost-benefit simulation was performed after statistical analysis.

RESULTS

There were 96 patients in the preintervention group and 110 in the postintervention group. The AKI rate decreased from 20% (n = 19) to 6% (n = 6; P = 0.003), whereas the number of vancomycin serum samples decreased from 5 (interquartile range: 2-7) to 2 (interquartile range: 1-3) examinations per patient ( P < 0.001). The mean length of hospital stay for patients was 26.19 days after vancomycin prescription, compared with 17.13 days for those without AKI ( P = 0.003). At our institution, the decrease in AKI rate and reduced length of stay boosted yearly savings of up to US$ 369,000 for 300 patients receiving vancomycin therapy.

CONCLUSIONS

Even in resource-limited settings, a commercial Bayesian forecasting-based protocol for vancomycin is important for determining cost-benefit outcomes.

Spanish Society of Hospital Pharmacy and the Spanish Society of Pediatric Infectious Diseases (SEFH-SEIP) National Consensus Guidelines for therapeutic drug monitoring of antibiotic and antifungal drugs in pediatric and newborn patients

Therapeutic monitoring of antibiotics and antifungals based on pharmacokinetic and pharmacodynamic parameters, is a strategy increasingly used for the optimization of therapy to improve efficacy, reduce the occurrence of toxicities, and prevent the selection of antimicrobial resistance, particularly in vulnerable patients including neonates and the critical or immunocompromised host. In neonates and children, infections account for a high percentage of hospital admissions and anti-infectives are the most used drugs. However, pediatric pharmacokinetic and pharmacodynamic studies and the evidence regarding the efficacy and safety of some newly marketed antibiotics and antifungals -usually used off-label in pediatrics- to determine the optimal drug dosage regimens are limited. It is widely known that this population presents important differences in the pharmacokinetic parameters (especially in drug clearance and volume of distribution) in comparison with adults that may alter antimicrobial exposure and, therefore, compromise treatment success. In addition, pediatric patients are more susceptible to potential adverse drug effects and they need closer monitoring. The aim of this document, developed jointly between the Spanish Society of Hospital Pharmacy (SEFH) and the Spanish Society of Pediatric Infectious Diseases (SEIP), is to describe the available evidence on the indications for therapeutic drug monitoring of antibiotics and antifungals in newborn and pediatric patients and to provide practical recommendations for therapeutic drug monitoring in routine clinical practice to optimize pharmacokinetic and pharmacodynamic parameters, efficacy and safety of antibiotics and antifungals in the pediatric population.

[Translated article] Therapeutic Drug Monitoring of antibiotic and antifungical drugs in paediatric and newborn patients. Consensus Guidelines of the Spanish Society of Hospital Pharmacy (SEFH) and the Spanish Society of Paediatric Infectious Diseases (SEIP)

Therapeutic monitoring of antibiotics and antifungals based on pharmacokinetic and pharmacodynamic (PK/PD) parameters is a strategy increasingly used for the optimization of therapy to improve efficacy, reduce the occurrence of toxicities, and prevent the selection of antimicrobial resistance, particularly in vulnerable patients including neonates and the critical or immunocompromised paediatric host. In neonates and children, infections account for a high percentage of hospital admissions, and anti-infectives are the most used drugs. However, paediatric PK/PD studies and the evidence regarding the efficacy and safety of some newly marketed antibiotics and antifungals-usually used off-label in paediatrics-to determine the optimal drug dosage regimens are limited. It is widely known that this population presents important differences in the PK parameters (especially in drug clearance and volume of distribution) in comparison with adults that may alter antimicrobial exposure and, therefore, compromise treatment success. In addition, paediatric patients are more susceptible to potential adverse drug effects and they need closer monitoring. The aim of this document, developed jointly by the Spanish Society of Hospital Pharmacy and the Spanish Society of Paediatric Infectious Diseases, is to describe the available evidence on the indications for therapeutic drug monitoring (TDM) of antibiotics and antifungals in newborn and paediatric patients, and to provide practical recommendations for TDM in routine clinical practice to optimise their dosing, efficacy and safety. Of antibiotics and antifungals in the paediatric population.

Model-informed precision dosing: State of the art and future perspectives

Model-informed precision dosing (MIPD) stands as a significant development in personalized medicine to tailor drug dosing to individual patient characteristics. MIPD moves beyond traditional therapeutic drug monitoring (TDM) by integrating mathematical predictions of dosing, and considering patient-specific factors (patient characteristics, drug measurements) as well as different sources of variability. For this purpose, rigorous model qualification is required for the application of MIPD in patients. This review delves into new methods in model selection and validation, also highlighting the role of machine learning in improving MIPD, the utilization of biosensors for real-time monitoring, as well as the potential of models integrating biomarkers for efficacy or toxicity for precision dosing. The clinical evidence of TDM and MIPD is discussed for various medical fields including infection medicine, oncology, transplant medicine, and inflammatory bowel diseases, thereby underscoring the role of pharmacokinetics/pharmacodynamics and specific biomarkers. Further research, particularly randomized clinical trials, is warranted to corroborate the value of MIPD in enhancing patient outcomes and advancing personalized medicine.

Dose optimization and target attainment of vancomycin in children

Vancomycin is a glycopeptide antibiotic that has been adopted in clinical practice to treat gram-positive infections for more than 70 years. Despite vancomycin's long history of therapeutic use, optimal dose adjustments and pharmacokinetic/pharmacodynamic (PK/PD) target attainment in children are still under debate. Therapeutic drug monitoring (TDM) has been widely integrated into pediatric clinical practice to maximize efficacy and safety of vancomycin treatment. Area under the curve (AUC)-guided TDM has been recently recommended instead of trough-only TDM to ensure PK/PD target attainment of AUC0-24h/minimal inhibitory concentration (MIC) > 400 to 600 and minimize acute kidney injury risk. Bayesian forecasting in pediatric patients allows estimation of population PK to accurately predict individual vancomycin concentrations over time, and consequently total vancomycin exposure. AUC-guided TDM for vancomycin, preferably with Bayesian forecasting, is therefore suggested for all pediatric age groups and special pediatric populations. In this review we aim to analyze the current literature on the pediatric use of vancomycin and summarize the current knowledge on dosing optimization for target attainment in special patient populations.

Therapeutic drug monitoring of glycopeptide antimicrobials: An overview of liquid chromatography-tandem mass spectrometry methods

Therapeutic drug monitoring (TDM) is a critical clinical tool used to optimize the safety and effectiveness of drugs by measuring their concentration in biological fluids. These fluids are primarily plasma or blood. TDM, together with real-time dosage adjustment, contributes highly to the successful management of glycopeptide antimicrobial therapies. Understanding pharmacokinetic/pharmacodynamic (PK/PD) properties is vital for optimizing antimicrobial therapies, as the efficacy of these therapies depends on both the exposure of the patient to the drug (PK) and pharmacodynamic (PD) parameters such as the in vitro estimated minimum drug concentration that inhibits bacterial growth (MIC). Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) is widely recognized as the gold standard for measuring small molecules, such as antibiotics. This review provides a comprehensive overview of LC-MS/MS methods available for TDM of glycopeptide antibiotics, including vancomycin, teicoplanin, dalbavancin, oritavancin, and telavancin.

A Method for Evaluating Robustness of Limited Sampling Strategies—Exemplified by Serum Iohexol Clearance for Determination of Measured Glomerular Filtration Rate

In combination with Bayesian estimates based on a population pharmacokinetic model, limited sampling strategies (LSS) may reduce the number of samples required for individual pharmacokinetic parameter estimations. Such strategies reduce the burden when assessing the area under the concentration versus time curves (AUC) in therapeutic drug monitoring. However, it is not uncommon for the actual sample time to deviate from the optimal one. In this work, we evaluate the robustness of parameter estimations to such deviations in an LSS. A previously developed 4-point LSS for estimation of serum iohexol clearance (i.e., dose/AUC) was used to exemplify the effect of sample time deviations. Two parallel strategies were used: (a) shifting the exact sampling time by an empirical amount of time for each of the four individual sample points, and (b) introducing a random error across all sample points. The investigated iohexol LSS appeared robust to deviations from optimal sample times, both across individual and multiple sample points. The proportion of individuals with a relative error greater than 15% (P15) was 5.3% in the reference run with optimally timed sampling, which increased to a maximum of 8.3% following the introduction of random error in sample time across all four time points. We propose to apply the present method for the validation of LSS developed for clinical use.