Candidates for area under the concentration-time curve (AUC)-guided dosing and risk reduction based on analyses of risk factors associated with nephrotoxicity in vancomycin-treated patients

Flowchart for predicting achieving the target area under the concentration-time curve of vancomycin in critically ill Japanese patients: A multicenter retrospective study

INTRODUCTION

In therapeutic drug monitoring (TDM) of vancomycin (VCM), the area under the concentration-time curve (AUC) is related to the clinical efficacy and toxicity. Therefore, herein, we examined the factors associated with achieving the target AUC at follow-up and developed a decision flowchart for achieving the target AUC in critically ill patients.

METHODS

This multicenter retrospective observational study was conducted at eight hospitals. We retrospectively analyzed data from patients who had received VCM in the intensive care unit from January 2020 to December 2022. Decision-tree (DT) analysis was performed using factors with p < 0.1 in univariate analysis as the independent variables. Case data were split up to two times, and four subgroups were included. The primary endpoint was achieving the target AUC at the follow-up TDM (AUCfollow-up) and target AUCfollow-up achievement was defined as an AUC of 400-600 μg‧h/mL. The initial AUC values were calculated with the 2-point concentrations (peak and trough) using the Bayesian estimation software Practical AUC-guided TDM (PAT).

RESULTS

Among 70 patients (median age [interquartile range], 66 [56, 79] years; 50 % women), the AUCfollow-up was achieved in 70 % (49/70). Three factors were selected for the decision flow chart: predicted AUCfollow-up of 400-600 μg‧h/mL, dosing at 12-h intervals, and CCr of 130 mL/min/1.73 m2 or higher; the accuracy was adequate (92 %, R2 0.52).

CONCLUSION

We successfully identified the factors associated with achieving the target AUC of VCM at follow-up TDM and developed a simple-to-use DT model. However, the validity of the findings needs to be evaluated.

Analysis of Vancomycin Dosage and Plasma Levels in Critically Ill Adult Patients Requiring Extracorporeal Membrane Oxygenation (ECMO)

Introduction: Critically ill patients undergoing extracorporeal membrane oxygenation (ECMO) exhibit unique pharmacokinetics. This study aimed to assess the achievement of vancomycin therapeutic targets in these patients. Methods: This retrospective cohort study included patients on ECMO treated with vancomycin between January 2010 and December 2018. Ninety patients were analyzed based on ECMO connection modality, baseline creatinine levels, estimated glomerular filtration rate (eGFR), renal replacement therapy (RRT) requirements, and vancomycin loading dose administration. Results: Twenty-three percent of the patients achieved the therapeutic range defined by baseline levels. No significant differences in meeting the therapeutic goal were found in multivariate analysis considering ECMO cannulation modality, initial creatinine level, initial eGFR, RRT requirement, or loading dose use. All trough levels between 15 and 20 mcg/mL achieved an estimated area under the curve/minimum inhibitory concentration (AUC/MIC) between 400 and 600, almost all trough levels over 10 mcg/mL predicted an AUC/MIC >400. Discussion: Achieving therapeutic plasma levels in these patients remains challenging, potentially due to factors such as individual pharmacokinetics and pathophysiology. A trough plasma level between 12 and 20 estimated the therapeutic AUC/MIC for all models, proposing a possible lower target, maintaining exposure, and potentially avoiding adverse effects. Despite being one of the largest cohorts of vancomycin use in ECMO patients studied, its retrospective nature and single-center focus limits its broad applicability.

Potential risk factors for early acute kidney injury in patients treated with vancomycin

PURPOSE

The acute kidney injury (AKI) onset owing to vancomycin (VCM) is reported that depend on the area under the blood concentration-time curve (AUC) and occur comparison early phase (early AKI). This study aimed to investigate the occurrence of early AKI in patients treated with VCM and new indicators to avoid early AKI.

METHODS

Adult patients who received VCM treatment for more than 4 days and whose trough values measured at least once on or after day 4 and serum creatinine before day 7 from the initiation of VCM administration between August 2021 and September 2022 at the Yamanashi Prefectural Central Hospital were enrolled. Early AKI (defined as AKI occurring within day 7 from VCM administration) and the association between each AUC (0-24, 24-48, 48-72, 0-48, 24-72, 0-72) were investigated. Furthermore, each AUC cut-off value for early AKI was calculated.

RESULT

In total, 164 patients were enrolled; early AKI developed in 21 patients and most frequently occurred on day 4. All stratified AUC were associated with early AKI development. The AUC cut-off values were AUC0-24: 470.8 μg/mL⋅h; AUC24-48: 473.0 μg/mL⋅h; AUC48-72: 489.7 μg/mL⋅h; AUC0-48: 910.2 μg/mL⋅h; AUC24-72: 1039.2 μg/mL⋅h; and AUC0-72: 1544.0 μg/mL⋅h.

CONCLUSION

The possibility of AKI development owing to the AUC accumulation of VCM was observed (accumulation toxicity). Concentration control through early-phase blood concentration measurements and a transition to AUC0-48 <910.2 μg/mL⋅h may reduce the early-phase AKI onset.

Vancomycin AUC-Based Dosing Practices in a Non-Teaching Community Hospital and Associated Outcomes: A One-Year Survey of Uniform Targets for Infections with or without MRSA

BACKGROUND

Intravenous (IV) vancomycin area under the curve (AUC)-based dosing is used uniformly for Gram-positive organisms in non-teaching community hospitals. However, evidence for using vancomycin AUC-based dosing for non-methicillin-resistant Staphylococcus aureus (non-MRSA) and less serious infections is limited in the literature. A gap in the literature also exists with respect to comparisons between the outcomes that can be derived using the regimens suggested by Bayesian programs and target doses of the AUC of 400-499 and 500-600.

METHODS

A retrospective review of all patients hospitalized in a non-teaching community hospital who used AUC-based vancomycin was performed over a 1-year period.

RESULTS

Only 17.6% of the included patients had confirmed MRSA. The values for the overall early response rate, 30-day all-cause mortality, and rate of acute kidney injury (AKI) were 50.3%, 11.3%, and 3.8%, respectively, in this population. In regression analysis, compared to non-MRSA infections, a significantly higher rate of early response was seen in patients with MRSA (unadjusted OR = 2.68, 95% CI [1.06-6.76] p = 0.04). Patients in the AUC 400-499 group had a non-significant higher incidence of 30 d mortality and new AKI compared to patients in the AUC 500-600 group. In our Kaplan-Meier survival analysis, there was no statistically significant difference between the comparison groups.

CONCLUSIONS

Early response was lower in patients with non-MRSA compared to patients with MRSA despite achieving the AUC target. There was no apparent difference in clinical outcomes between the higher and lower AUC groups. Further large-scale research is needed to confirm these findings.

Simulation of Vancomycin Exposure Using Trough and Peak Levels Achieves the Target Area under the Steady-State Concentration-Time Curve in ICU Patients

The therapeutic drug monitoring (TDM) of vancomycin (VCM) in critically ill patients often results in the estimated area being under the concentration-time curve (AUC) values that deviate from individual observations. In this study, we investigated the factors influencing the achievement of the target AUC of VCM at steady-state in critically ill patients. We retrospectively collected data from patients treated with VCM in an intensive care unit (ICU). Multivariate analysis was used to adjust for significant factors with p < 0.05 and identify new factors affecting the achievement of the target AUC at steady-state for VCM. Among the 113 patients included in this study, 72 (64%) were in the 1-point group (trough only), whereas 41 (36%) were in the 2-point group (trough/peak). The percentage of patients achieving the target AUC at the follow-up TDM evaluation was significantly higher in the two-point group. Multivariate analysis showed that being in the 2-point group and those with a 20% or more increase (or decrease) in creatinine clearance (CCr) were both significantly associated with the success rate of achieving the target AUC at the follow-up TDM. Novel findings revealed that in patients admitted to the ICU, changes in renal function were a predictor of AUC deviation, with a 20% or more increase (or decrease) in CCr being an indicator. We believe the indicators obtained in this study are simple and can be applied clinically in many facilities. If changes in renal function are anticipated, we recommend an AUC evaluation of VCM with a two-point blood collection, close monitoring of renal function, and dose adjustment based on reanalyzing the serum concentrations of VCM.

Development and Evaluation of a Novel Software Program, SAKURA-TDM, for Area Under the Concentration-Time Curve-Guided Vancomycin Dosing: A Short Communication

BACKGROUND

The area under the concentration-time curve (AUC)-guided dosing of vancomycin has been introduced in Japan; however, the optimal dosing method remains controversial. Here, a novel software program was developed for AUC-guided vancomycin dosing and to estimate the theoretical threshold of the steady-state AUC 24 that could reduce the risk of renal injury.

METHODS

A single-center, retrospective, observational study was conducted to develop a novel software program (SAKURA-TDM ver.1.0) for AUC-guided dosing. The estimation accuracy of pharmacokinetic parameters determined using SAKURA-TDM was compared with that of clinically available software programs and assessed with Bland-Altman analysis. In addition, theoretical cutoff points of the steady-state AUC 24 and the predicted trough values were estimated using Youden J statistic approach.

RESULTS

The estimation accuracy of pharmacokinetic parameters and AUC determined using SAKURA-TDM was comparable to that of other TDM software programs. Of note, despite a good relationship between the predicted AUC 24 and trough values, the correlation between the predicted AUC 24 and measured trough values was not strong. The cutoff values of the steady-state AUC 24 and the predicted trough value for reducing the probability of a measured trough value of >20 mcg/mL were 513.1 mg·h/L and 15.6 mcg/mL, respectively.

CONCLUSIONS

We demonstrated the equivalence of the estimated PK parameters between SAKURA-TDM and other TDM software programs available in Japan. Considering the threshold of both trough values and the steady-state AUC and monitoring of the AUC in a non-steady state, it would be possible to reduce the risk of vancomycin-associated renal injury.

Evaluating the Nephrotoxicity of Area-under-the-Curve-Based Dosing of Vancomycin with Concomitant Antipseudomonal Beta-Lactam Antibiotics: A Systematic Review and Meta-Analysis

Background and Objectives: Vancomycin combined with piperacillin/tazobactam (vancomycin + piperacillin/tazobactam) has a higher risk of acute kidney injury (AKI) than vancomycin combined with cefepime or meropenem. However, it is uncertain if applying area under the curve (AUC)-based vancomycin dosing has less nephrotoxicity than trough-based dosing in these combinations. Materials and Methods: We searched PubMed, Embase, Cochrane Library, and ClinicalTrials.gov from inception to December 2022. We examined the odds ratio (OR) of AKI between vancomycin + piperacillin/tazobactam and the control group. The control group was defined as vancomycin combined with antipseudomonal beta-lactam antibiotics, except for piperacillin-tazobactam. Results: The OR for AKI is significantly higher in vancomycin + piperacillin/tazobactam compared with the control group (3 studies, 866 patients, OR of 3.861, 95% confidence interval of 2.165 to 6.887, p < 0.05). In the sample population of patients who received vancomycin + piperacillin/tazobactam (2 studies, 536 patients), the risk of AKI (OR of 0.715, 95% CI of 0.439 to 1.163, p = 0.177) and daily vancomycin dose (standard mean difference—0.139, 95% CI—0.458 to 0.179; p = 0.392) are lower by AUC-based dosing than trough-based dosing, although it is not statistically significant. Conclusions: Nephrotoxicity is higher when combined with piperacillin/tazobactam than other antipseudomonal beta-lactam antibiotics (cefepime or meropenem) using the AUC-based dosing. However, applying the AUC-based dosing did not eliminate the risk of AKI or significantly reduce thedaily vancomycin dose compared with the trough-based dosing in the available literature.

Evaluation of vancomycin pharmacokinetics in patients with augmented renal clearances: A randomized clinical trial

Purpose: Vancomycin is a narrow therapeutic window glycopeptide antibiotic that acts against Gram-positive bacteria. As it is renally eliminated, therapeutic drug monitoring is recommended for vancomycin, especially in case of kidney function alteration. Augmented renal clearance (ARC), defined as a creatinine clearance of more than 130 ml/min, is a risk factor for sub-therapeutic concentrations of vancomycin. This study aimed to evaluate the vancomycin pharmacokinetics following the administration of two different regimens in ARC patients.

Methods: A randomized clinical trial (IRCT20180802040665N1) was conducted on patients in need of vancomycin therapy. Eight hours of urine was collected and 56 patients divided into two groups with creatinine clearance of more than 130 ml/min were included in the study. The first group received 15 mg/kg of vancomycin every 12 h and the second group 15 mg/kg every 8 h. After four doses, the peak and trough concentrations were measured from two blood samples. The primary outcome was the percentage of patients who attainted AUC more than 400. The occurrence of acute kidney injury also was evaluated after seven days.

Results: The mean age of patients in the every 12 h and every 8 h groups was 44.04 ± 16.55 and 42.86 ± 11.83 years, respectively. While neurosurgical issues were the most common causes of hospitalization, central nervous infections were the most common indications for vancomycin initiation. Urinary creatinine clearance was 166.94 ± 41.32 ml/min in the every 12 h group and 171.78 ± 48.56 ml/min in the every 8 h group. 46.42% of patients in the every 12 h group and 82.14% of patients in the every 8 h group attained AUC/MIC of more than 400 mg × hr/L. None of the patients in the every 12 h group reached more than 15 mcg/ml concentration. At the 7-day follow-up, 10.7% patients in the BD group and 28.6% patients in the TDS group developed acute kidney injury (p = 0.089).

Conclusion: Administration of vancomycin at a dose of 15 mg/kg every 8 h is associated with higher pharmacokinetic attainment in ARC patients. The occurrence of acute kidney injury also was not significantly higher in this therapeutic regimen. AUC/MIC monitoring is necessary in this population.

Current Aspects of Pediatric Pharmacokinetics and Pharmacodynamics of Antimicrobials in Japan: Importance of the Promotion of Population PK/PD Analysis

Pharmacologic knowledge is important for pediatricians conducting feasible pharmacokinetic or pharmacodynamic (PK/PD) studies or applying effective antimicrobial therapies in children. Because of the difficulties in conducting PK/PD studies in children, antimicrobial PK/PD data in children are still limited. To fill in the lack of knowledge, promotion of population PK/PD analysis, which allows us to handle sparse sampling data from individual patients, is important because it is considered a suitable methodology to conduct PK/PD studies in children with limited blood drug concentration data for PK/PD analysis. Population PK/PD analysis is also useful in the clinical setting to provide individualized optimal dosage for each patient with various conditions. Here we summarized the current aspects of pediatric PK/PD studies of antimicrobials in Japan from clinical and research perspectives, specifically focusing on the importance of population PK/PD analysis.

Prediction Accuracy of Area under the Concentration-Time Curve of Vancomycin by Bayesian Approach Using Creatinine-Based Equations of Estimated Kidney Function in Bedridden Elderly Japanese Patients

An administration plan for vancomycin (VCM) in bedridden elderly patients has not been established. This retrospective study aimed to evaluate the prediction accuracy of the area under the concentration-time curve (AUC) of VCM by the Bayesian approach using creatinine-based equations of estimated kidney function in such patients. Kidney function was estimated using the Japanese equation of estimated glomerular filtration rate (eGFR) and the Cockcroft-Gault equation of estimated creatinine clearance (eCCr). eCCr (serum creatinine (SCr) + 0.2) was calculated by substituting the SCr level +0.2 mg/dL into the Cockcroft-Gault equation. For eGFR/0.789, eGFR, eCCr, and eCCr (SCr + 0.2), the AUC values were calculated by the Bayesian approach using the therapeutic drug monitoring (TDM) software, BMs-Pod (ver 8.06) and denoted as AUC_eGFR/0.789, AUC_eGFR, AUC_eCCr, and AUC_{eCCr (SCr + 0.2)} respectively. The reference AUC (AUC_REF) was calculated by applying VCM's peak and trough steady-state concentrations to first-order pharmacokinetic equations. The medians (range) of AUC_eGFR/0.789/AUC_REF, AUC_eGFR/AUC_REF, AUC_eCCr/AUC_REF, and AUC_{eCCr (SCr + 0.2)}/AUC_REF were 0.88 (0.74-0.93), 0.90 (0.79-1.04), 0.92 (0.81-1.07), and 1.00 (0.88-1.11), respectively. Moreover, the percentage of patients within 10% of the AUC_REF, defined as |Bayesian-estimated AUC - AUC_REF| < AUC_REF × 0.1, was the highest (86%) in AUC_{eCCr (SCr + 0.2)}. These results suggest that the Bayesian approach using eCCr (SCr + 0.2) has the highest prediction accuracy for the AUC_REF in bedridden elderly patients. Although further studies are required with more accurate determination methods of the CCr and AUC, our findings highlight the potential of eCCr (SCr + 0.2) for estimating VCM's AUC by the Bayesian approach in such patients.

Clinical Practice Guidelines for Therapeutic Drug Monitoring of Vancomycin in the Framework of Model-Informed Precision Dosing: A Consensus Review by the Japanese Society of Chemotherapy and the Japanese Society of Therapeutic Drug Monitoring

Background: To promote model-informed precision dosing (MIPD) for vancomycin (VCM), we developed statements for therapeutic drug monitoring (TDM). Methods: Ten clinical questions were selected. The committee conducted a systematic review and meta-analysis as well as clinical studies to establish recommendations for area under the concentration-time curve (AUC)-guided dosing. Results: AUC-guided dosing tended to more strongly decrease the risk of acute kidney injury (AKI) than trough-guided dosing, and a lower risk of treatment failure was demonstrated for higher AUC/minimum inhibitory concentration (MIC) ratios (cut-off of 400). Higher AUCs (cut-off of 600 μg·h/mL) significantly increased the risk of AKI. Although Bayesian estimation with two-point measurement was recommended, the trough concentration alone may be used in patients with mild infections in whom VCM was administered with q12h. To increase the concentration on days 1–2, the routine use of a loading dose is required. TDM on day 2 before steady state is reached should be considered to optimize the dose in patients with serious infections and a high risk of AKI. Conclusions: These VCM TDM guidelines provide recommendations based on MIPD to increase treatment response while preventing adverse effects.

A Strategy for Hospital Pharmacists to Control Antimicrobial Resistance (AMR) in Japan

In Japan, there is concern regarding the relation between the inappropriate use of antibiotics and antibiotic resistance (AMR). Increased bacterial resistance is due in part to the inappropriate use of antimicrobial agents. The support of the pharmacist becomes important, and there is growing interest in antimicrobial stewardship to promote the appropriate and safe use of antimicrobials needed for the optimal selection of drugs, doses, durations of therapy, therapeutic drug monitoring (TDM), and implementations of cost containment strategies in Japan. Pharmacists should strive to disseminate the concept of "choosing wisely" in relation to all medicines, implement further interventions, and put them into practice. In this article, we present data for antimicrobial stewardship and Japan's AMR action plan, focusing on how pharmacists should be involved in enabling physicians to choose antimicrobials wisely.