Should the trough concentration of vancomycin be abandoned in therapeutic drug monitoring? A multicentre, retrospective study of critically ill patients without any form of dialysis.

BACKGROUND: There are conflicts in guideline recommendations about the value and range of vancomycin trough concentration during therapeutic drug monitoring (TDM). This multicentre, retrospective study was conducted to explore the usefulness of trough concentration in specific patients who were critically ill and without any form of dialysis. METHODS: Patient information from five centres was retrospectively collected and the 24-hour area under the curve (AUC) was estimated by a Bayesian method. Patients were categorised into four groups according to trough concentration: < 10, 10-15, 15-20 and > 20 mg/L, and the corresponding AUC was analysed. A multivariable logistic regression model was used to investigate the relationship between trough concentration and AUC. RESULTS: Overall, 645 trough concentrations available from 416 patients were included in this study. The results indicated that the AUC was always < 400 mg/L∙h or > 600 mg/L∙h in the < 10 or > 20 mg/L groups, whereas the ratios of vancomycin AUC target attainment (400-600 mg/L∙h) were 48.8% and 92.3% in the 10-15 mg/L and 15-20 mg/L groups, respectively. Augmented renal clearance, low daily dose and non-q12h administration were found to be independent risk factors associated with AUC target non-attainment for patients with trough concentrations of 10-15 mg/L. CONCLUSION: Vancomycin trough concentration is a good marker of AUC for critically ill adults without any form of dialysis. However, AUC-guided TDM may be needed for patients with trough concentrations of 10-15 mg/L, especially for those with risk factors.