A RETROSPECTIVE EVALUATION OF THE IMPACT OF VANCOMYCIN AUC DOSING ON ACUTE KIDNEY INJURY AND DRUG EXPOSURE IN HOSPITALIZED PATIENTS.
Shemaiah Caine, Deanne Tabb, Tushar Patel, Aayush Patel Piedmont Columbus Regional Midtown Columbus, GA
Background/Purpose: Vancomycin trough-based monitoring is associated with excessive exposure and increased acute kidney injury (AKI). however, trough-based monitoring is associated with excessive drug exposure and increased risk of acute kidney injury (AKI). ASHP/IDSA consensus guidelines recommend AUC guided dosing with a target AUC of 400 - 600 mg·hr/L to improve safety and efficacy. In January 2025, Piedmont Columbus Regional Midtown implemented InsightRX®, a Bayesian dosing platform designed to support individualized AUC guided vancomycin dosing. The purpose of this study is to assess the impact of this transition on AKI incidence and drug exposure.
Methodology: This retrospective single center pre/post cohort study will include adult patients who received ≥ 72 hours of intravenous vancomycin, comparing a trough-based cohort (Oct-Dec 2024) with an AUC guided cohort after InsightRX® implementation (Jun-Aug 2025). Data from Epic and InsightRX® will capture demographics, baseline renal function, vancomycin dosing characteristics, and nephrotoxin exposure. The primary outcome is AKI during therapy or within 48 hours after the last dose, defined per KDIGO criteria. Secondary outcomes include time to target AUC, number of levels drawn, trough distributions, and total vancomycin exposure. Continuous variables will be analysed using a two-sample t-test, and categorical variables using Fisher’s exact test.
Results: For the primary outcome, AKI occurred in approximately 9% of patients in the trough-based group compared with 7% in the AUC-guided group. The p-value of 1.00 suggests there was no statistically significant difference between groups. However, given the small sample size and descriptive design, this analysis was likely underpowered to detect meaningful differences in AKI risk. For secondary outcomes, average vancomycin exposure within the first 72 hours was similar between groups, at approximately 2,300 mg/day in the trough-based cohort and 2,208 mg/day in the AUC-guided cohort, with no statistically significant difference observed, p=0.64. However, a greater proportion of patients in the AUC-guided group achieved target therapeutic exposure within 48 hours compared with the trough-based group, 56% versus 18%, respectively, which was statistically significant with a p-value of 0.005. Within the trough-based cohort, most patients, 68%, had trough concentrations between 11 and 14.9 mcg/mL, while 27% were between 15 and 20 mcg/mL. Only one patient had a trough concentration greater than 20 mcg/mL.
Conclusions: AUC guided vancomycin dosing was associated with a significantly higher rate of early target attainment within 48 hours compared to trough-based dosing. Despite this difference, overall vancomycin exposure within the first 72 hours of therapy was similar between groups, suggesting comparable initial dosing intensity. There was no statistically significant difference in the incidence of acute kidney injury between the two strategies; however, this study was likely underpowered to detect meaningful differences in safety outcomes. Overall, these findings suggest that AUC guided dosing may improve early pharmacokinetic target achievement without increasing nephrotoxicity, though larger studies are needed to further evaluate its impact on renal outcomes.
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