A Quasi-Experimental Evaluation of Single Trough-Based Area Under the Curve Guided Dosing on the Incidence of Vancomycin Associated Nephrotoxicity in Veteran Patients.

Background: Two common dosing strategies for vancomycin are trough-based and area under the curve (AUC)-based dosing. Objective: To compare the incidence of nephrotoxicity in trough-based dosing group with the single trough-based AUC dosing at the Salem VA Medical Center. Methods: This retrospective study included patients who received trough-based dosing of vancomycin between January 1, 2017, and January 1, 2019 (preimplementation group) and AUC-based dosing (postimplementation) between October 1, 2019, and October 1, 2021, at the Salem VA Medical Center. The primary outcome was nephrotoxicity at 96 hours, 7 days, and entire hospital length of stay (LOS). Secondary outcomes included 30-day readmission and all-cause mortality rates, cumulative doses at 24, 48, and 72 hours, and percentage of patients considered at goal (AUC 400-600 or trough between 10 and 20 mg/L). Propensity score (PS) matching was utilized to adjust for confounding. Results: After PS matching 100 patients were included in preimplementation and 95 patients in the postimplementation group. The average study patient was a 68-year-old white male. There was significant reduction in the risk of nephrotoxicity in postimplementation cohort at 96 hours (adjusted (a)HR: 0.28, 95% CI (0.12-0.66); 7 days (aHR: 0.39, 95% CI (0.18-0.85); and entire hospital LOS (aHR: 0.46, 95% CI (0.22-0.95). Secondary outcomes showed no difference between the groups except significantly higher proportion of patients were considered at therapeutic goal in the postimplementation cohort compared with pre-implementation cohort. Conclusion: This hypothesis generating study shows that AUC-based dosing calculated using single trough concentration may result in reduced rate of nephrotoxicity than trough-based dosing.