Impact of an Antimicrobial Stewardship Program on Patient Safety in Veterans Prescribed Vancomycin

Abstract Purpose This study aimed to determine the safety impact of an antimicrobial stewardship program (ASP) on vancomycin-associated nephrotoxicity and to examine risk factors contributing to the development of toxicity. Methods This was a retrospective chart review of data from 453 veterans receiving vancomycin in the VA Western New York Healthcare System between October 2006 and July 2014. Nephrotoxicity was defined as an increase in serum creatinine of ≥0.5 mg/dL or by 50% of baseline for 2 consecutive days. Findings Patients receiving vancomycin after the implementation of the ASP were less likely to develop nephrotoxicity (odds ratio [OR] = 2.06; 95% CI, 1.02–4.28). Nephrotoxicity occurred in 6.84% of patients from the pre-ASP cohort and in 3.75% of patients after the implementation of the ASP. Predictors of nephrotoxicity included hospital service (surgical service, OR = 2.29; 95% CI, 1.13–4.64), elevated maximum trough concentration (unit OR = 1.15; 95% CI, 1.10–1.20), and concurrent piperacillin/tazobactam therapy (OR = 3.21; 95% CI, 1.43–7.96). The number of vancomycin trough concentration measurements per patient did not vary between the pre-ASP and ASP groups. Implications ASPs represent an important aspect of a patient-safety initiative in order to reduce vancomycin-associated nephrotoxicity. Concurrent piperacillin/tazobactam therapy, surgical service, and elevated maximum trough concentration were risk factors for nephrotoxicity.