The Bayesian-Based Area under the Curve of Vancomycin by Using a Single Trough Level: An Evaluation of Accuracy and Discordance at Tertiary Care Hospital in KSA.

The AUC0-24 is the most accurate way to track the vancomycin level while the Cmin is not an accurate surrogate. Most hospitals in Saudi Arabia are under-practicing the AUC-guided vancomycin dosing and monitoring. No previous work has been conducted to evaluate such practice in the whole kingdom. The current study objective is to calculate the AUC0-24 using the Bayesian dosing software (PrecisePK), identify the probability of patients who receive the optimum dose of vancomycin, and evaluate the accuracy and precision of the Bayesian platform. This retrospective study was conducted at King Abdulaziz medical city, Jeddah. All adult patients treated with vancomycin were included. Pediatric patients, critically ill patients requiring ICU admission, patients with acute renal failure or undergoing dialysis, and febrile neutropenic patients were excluded. The AUC0-24 was predicted using the PrecisePK platform based on the Bayesian principle. The two-compartmental model by Rodvold et al. in this platform and patients' dose data were utilized to calculate the AUC0-24 and trough level. Among 342 patients included in the present study, the mean of the estimated vancomycin AUC0-24 by the posterior model of PrecisePK was 573 ± 199.6 mg, and the model had a bias of 16.8%, whereas the precision was 2.85 mg/L. The target AUC0-24 (400 to 600 mg·h/L) and measured trough (10 to 20 mg/L) were documented in 127 (37.1%) and 185 (54%), respectively. Furthermore, the result demonstrated an increase in odds of AUC0-24 > 600 mg·h/L among trough level 15-20 mg/L group (OR = 13.2, p < 0.05) as compared with trough level 10-14.9 mg/L group. In conclusion, the discordance in the AUC0-24 ratio and measured trough concentration may jeopardize patient safety, and implantation of the Bayesian approach as a workable alternative to the traditional trough method should be considered.

Augmented Renal Clearance and Hypoalbuminemia-Induced Low Vancomycin Trough Concentrations in Febrile Neutropenic Patients With Hematological Malignancies.

INTRODUCTION: Vancomycin administration in individuals with hematological malignancy or neutropenia is associated with a suboptimal trough concentration. Nonetheless, most studies did not distinguish whether low vancomycin trough concentrations were due to hematological malignancies or neutropenia. This study aimed to determine the association between types of hematological malignancy and febrile neutropenia with low vancomycin concentrations. METHODS: The present retrospective chart review study was conducted by using clinical data adopted from computerized physician order entries (BestCare®) for all of the patients who received intravenous vancomycin treatment between January 2017 and December 2020 at King Abdulaziz Medical City in Jeddah. RESULTS: Out of the 296 patients, 217 were included. There was no significant association between the type of hematological malignancy and the incidence of a low trough concentration (p > 0.05), while a significant association between febrile neutropenia and the incidence of a low trough concentration was observed (p < 0.05). Furthermore, the predictors for a low trough among febrile neutropenic patients were creatinine clearance (CrCI) and a low albumin concentration. In addition, there was a significant association between febrile neutropenia and augmented renal clearance (p < 0.05). CONCLUSIONS: The findings of this study conclude that febrile neutropenia is associated with low vancomycin concentrations. Interestingly, augmented renal clearance was observed in most of the febrile neutropenia patients with a significant association, which is considered the main driver for a low trough in neutropenic patients.

Causes of vancomycin dosing error; problem detection and practical solutions; a retrospective, single-center, cross-sectional study.

Vancomycindosing error and inappropriate monitoring is a common problem in hospital daily practice. In King Abdulaziz Medical City (KAMC) in Jeddah, a high percentage of abnormal vancomycin trough levels is still detected despite using the recommended dose. Therefore, the current research objective is to study the major causes of vancomycin dosing errors. This retrospective, single-center, cross-sectional study was carried out at KAMC hospital in Jeddah from January 1st until December 31st 2019. All adult patients (≥15 years) who received vancomycin and had an initial abnormal trough level at the measured steady-state were included in this study. 472 patients have met the study inclusion criteria. The current study evaluated the factors that play a role in causing vancomycin trough level abnormalities such as sampling time, vancomycin dosing, and patient's pharmacokinetic and pharmacodynamic variations. In this study, we found that pharmacokinetic and pharmacodynamic variability was attributed to 65% of vancomycin's abnormal trough level. Also, the result showed a significantly increased odds of the low trough in the non-elderly group (OR 6, 95% CI 2.48 - 14.9, P < 0.001) and febrile neutropenic patients (OR 2.21, 95% CI 1.119 - 4.365, P < 0.05). However, the odds of high trough levels were significantly elevated among patients who have CrCl < 50 ml/min (OR 5, 95% CI 1.262-20.539, P < 0.05). In addition, the present investigation revealed that the occurrence of abnormal vancomycin levels was not affected by daily duty time or working days (p > 0.05). The current study indicated that vancomycin dosing errors were common in KAMC patients; thus, there is an unmet need to evaluate the causes of vancomycin abnormal trough level and optimize a strategy that would enhance the therapeutic effectiveness and minimize the potential toxicity.