Impact of Higher Vancomycin Troughs on Vancomycin-Induced Nephrotoxicity

Abstract

Background Guidelines published in 2009 by the Infectious Diseases Society of America, the American Society of Health-System Pharmacists, and the Society of Infectious Diseases Pharmacists recommended targeting vancomycin troughs of 15 to 20 mg/L. No previous studies exist examining the effect of implementing these guidelines on kidney function. The objective of this study was to evaluate the effect of a dosing nomogram that incorporated recommendations for higher vancomycin goal trough vancomycin-induced nephrotoxicity (VIN). Methods This study evaluated 300 adult inpatients with a pharmacokinetics consultation for vancomycin dosing. Two periods were evaluated: phase I (2008) assessed practice preguideline vancomycin dosing nomogram change, and phase II (2012) assessed practice postguideline vancomycin dosing nomogram change reflecting the higher trough targets. Groups were compared using χ2 or Fisher exact tests for categorical variables and Mann-Whitney U tests for continuous variables. The a priori level of significance was set at 0.05. Results A total of 300 inpatients (150 in 2008 and 150 in 2012) were included in the analysis. More patients from the 2012 group experienced VIN, according to the guideline definition (P = 0.03), but not per the 2007 Acute Kidney Injury Network definition (P = 0.88). There was no change in other adverse outcomes, including dialysis initiation (2 vs 0; P = 0.16), discharge on dialysis (1 vs 0; P = 0.32), transfer to another hospital for higher level of care (33 vs 34; P = 0.89), or death (15 vs 11; P = 0.41). Conclusions Targeting higher vancomycin troughs resulted in transient VIN but did not cause adverse sequelae.