BAYESIAN ESTIMATION VERSUS FIRST-ORDER PHARMACOKINETIC EQUATIONS FOR AUC-GUIDED VANCOMYCIN DOSING: A NARRATIVE REVIEW

Background: Consensus guidelines recommend area under the curve (AUC) guided vancomycin monitoring for severe infections caused by methicillin-resistant Staphylococcus aureus. This targets an AUC24/MIC ratio of 400-600 assuming a MIC of 1mg/L. An AUC can be calculated using first-order equations or Bayesian software based on two concentrations. Despite both being recommended, there is little information available on how they differ from each other.
Objective: To review the principles, evidence, practicalities and research requirements of Bayesian vs. equation-based AUC estimation for vancomycin.
Approach: Narrative review of guideline documents and published comparative studies of AUC estimation methods. The literature search methods must be completed by the authors before submission, including databases, final search date, search terms, and selection criteria.
Findings: Limited studies were comparing AUC estimation techniques. Most were single-centre and retrospective. Overall, there was good agreement between first-order and Bayesian estimates for adult and paediatric patients. Bayesian techniques allow for earlier estimates and more flexible sampling. One quasi-experimental study found more useful concentrations. However, benefits depend on integration with electronic health records. There is no evidence to suggest one technique will lead to differences in nephrotoxicity, efficacy or mortality. There is strong evidence to suggest AUC-guided monitoring will result in less nephrotoxicity than trough.
Conclusion: Both techniques will give acceptable estimates of AUC if used appropriately. Choice should be based on sampling ability, patient population, model appropriateness and local resources. More prospective studies comparing the techniques and focusing on patient-centred outcomes are needed. Keywords: vancomycin, therapeutic drug monitoring, area under the curve, Bayesian estimation, pharmacokinetics, acute kidney injury.