Implementation of AUC-Guided Vancomycin Dosing: What Role Remains for Trough-Only Monitoring? A Retrospective, Cohort Study

BackgroundThe 2020 consensus guidelines for drug monitoring of vancomycin recommended AUC-guided dosing to reduce acute kidney injury (AKI) and improve clinical outcomes in patients with serious methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) infections previously managed with trough concentrations of 15-20 mg/L.ObjectivesTo determine if AUC-guided dosing of vancomycin reduces AKI and improves clinical outcomes including non-invasive infections with <i>S. aureus</i> compared with trough-only dosing broadened to concentrations of 10-20 mg/L.MethodsA retrospective, single-center, cohort study was conducted over 12 months comparing Bayesian software-guided AUC-dosing with trough-only dosing. Information collected included patient demographics, co-morbidities, concurrent nephrotoxins, assessment measures of drug exposure, and patient outcomes. Nominal data were analyzed using the chi-square test, and continuous data using the independent <i>t</i> test.ResultsBased on the Kidney Disease Improving Global Outcomes (KDIGO) criteria, the incidence of AKI was 7.65% and 6.06% (<i>P</i> = 0.56), among 183 patients in the AUC-guided and 165 subjects in the trough-only groups, respectively. Individuals in the trough-only group were younger, had fewer co-morbidities and admissions to the ICU. A lower incidence of AKI findings among trough-only subjects was likely a result of the duration of therapy (mean of 4.2 days), mean trough concentrations <15 mg/L, and fewer concurrent nephrotoxins. AUC-guided dosing significantly reduced the total daily dose, 2.29 vs 2.54 g/day (<i>P</i> = 0.01), but provided no significant reductions in cumulative dose, duration of therapy, length of hospital stays, or overall patient outcomes.ConclusionAUC-guided vancomycin dosing did not reduce the incidence of AKI nor impact patient outcomes vs trough-only dosing. Successful clinical outcomes with lower average trough concentrations may have resulted from the treatment of nonbacteremic skin soft tissue infections (SSTI), suggesting an indication for further exploration of vancomycin dosing strategies.