Evaluating the clinical impact of targeting lower versus higher serum vancomycin trough: a retrospective study using a desirability of outcome ranking (DOOR) analysis.

PURPOSE

Guidelines recommend a target AUC/MIC of 400-600 for vancomycin dosing in serious MRSA infections. However, various challenges hinder the implementation of AUC-based monitoring. Previously recommended target trough of 15-20 mg/L may be associated with increased nephrotoxicity.

METHODS

In this single-center, retrospective study, we compared outcomes of targeting troughs of 10-15 mg/L vs 15-20 mg/L for intermittent infusion of vancomycin (IIV) in adult hospitalized patients who received ≥ 48 h of IIV and had ≥ 1 trough measurement within recommended ranges. Local guidelines recommended target troughs of 15-20 mg/L between January 2019 and December 2020 and 10-15 mg/L between January 2022 and October 2023. Treatment failure, acute kidney injury (AKI) and inpatient mortality were compared using a desirability of outcome ranking (DOOR) analysis between the two time periods. The most desirable outcome was treatment success and no AKI, and the least desirable outcome was death.

RESULTS

A total of 173 IIV courses were included. The probability of obtaining a better DOOR was 57.9% (95%CI 50.5-64.9, p = 0.03) when targeting a lower trough. Secondary analyses demonstrated a similar trend. When analyzed separately, the lower target trough group experienced significantly less AKI (OR 0.40, 95%CI 0.16-0.96) with no significant effect on mortality and treatment failure.

CONCLUSION

Our study showed that targeting a trough of 10-15 mg/L for IIV may be associated with a superior overall outcome compared to targeting 15-20 mg/L. In centers not using AUC-based monitoring for vancomycin dosing, a lower target trough may be preferable.