Dual therapeutic interventions to optimize vancomycin exposure and reduce nephrotoxicity: a cohort study from a single center

BACKGROUND: Vancomycin-associated Acute Kidney Injury (AKI) is a significant global concern, increasing healthcare costs, morbidity, and mortality. This Quality Improvement Project (QIP) aimed to reduce supratherapeutic vancomycin concentrations and AKI by lowering the trough target and implementing AUC (Area Under the Curve)-based dosing. METHODS: This was a single-center cohort study. Adult patients receiving intravenous vancomycin for at least 72 h were prospectively recruited from January to June 2022. Vancomycin trough target was revised from 15 to 20 mg/L to 10-20 mg/L, and a hybrid dosing strategy incorporating AUC-based dosing for eligible patients was piloted in five wards. A historical cohort from June to November 2021, managed with higher trough target of 15-20 mg/L, was investigated for comparison. The primary outcome was the rate of supratherapeutic vancomycin trough concentrations (> 20 mg/L). Secondary outcomes included AKI incidence, total vancomycin dose over the initial 72 h, in-hospital mortality, and operational metrics related to therapeutic drug monitoring. RESULTS: A total of 80 patients in the historical cohort and 57 in the QIP cohort were analysed. The rate of supratherapeutic vancomycin trough concentrations was lower in the QIP cohort compared with the historical cohort (11% vs. 20%, p < 0.01). AKI rate was lower in the QIP cohort, although not statistically significant (12% vs. 18%). In-hospital mortality was numerically lower in the QIP cohort (3.5% vs. 7.5%). The total vancomycin dose administered during the initial 72 h was significantly lower in the QIP cohort (83 [56-100] vs. 104 [76-119] mg/kg, p < 0.01). Vancomycin concentrations were monitored less frequently, while dose adjustments were similar between cohorts. CONCLUSION: Lowering the vancomycin trough target and adopting AUC dosing in selected patients reduced supratherapeutic vancomycin concentrations, and showed potential to lower nephrotoxicity, without requiring increased monitoring or dose adjustments. However, the small number of patients receiving AUC-guided dosing limits interpretation of its specific contribution.