Vancomycin Use in Patients Discharged From the Emergency Department: A Retrospective Observational Cohort Study

Abstract

Background: Infections due to methicillin-resistant Staphylococcus aureus (MRSA) are associated with significant morbidity and mortality and are typically treated with intravenous vancomycin. Given vancomycin's time-dependent mechanism of action, it is unlikely that vancomycin administration in the emergency department (ED) prior to disposition home could be beneficial.

Study objectives: To characterize the indications, dosing, and appropriateness of vancomycin use in patients discharged from the ED.

Methods: This is a single-center retrospective observational cohort study of patients who received vancomycin in an urban, academic, tertiary care ED. The subjects were consecutive adult patients administered intravenous vancomycin in the ED and then discharged home over an 18-month period. Outcomes were measured 1) to characterize patients receiving vancomycin prior to discharge home from the ED; and 2) to identify patients that did not meet indications for appropriate use based on the 2011 Infectious Diseases Society of America guidelines for treating MRSA infections.

Results: There were 526 patients that received vancomycin in the ED prior to discharge during the study period. In this cohort, 368 (70%) patients were diagnosed with skin and soft tissue infections. A MRSA risk factor was present in 396 (75%) patients. Prior to discharge, one dose of vancomycin was administered to 357 (68%) patients. Underdosing of vancomycin occurred in 239 (73%) patients.

Conclusions: Vancomycin was given frequently to patients discharged home from the ED, most commonly for conditions where vancomycin was not indicated, such as skin and soft tissue infections. The majority of these patients received a vancomycin dosing strategy that is not only unlikely to lead to clinical improvement, but also has the potential to contribute adversely to the development of antibiotic resistance. Further investigation is needed into the impact of vancomycin use, the emergence of vancomycin resistance, and the role of ED-based antibiotic stewardship.

Keywords: antibiotic stewardship; emergency department; methicillin-resistant Staphylococcus aureus (MRSA); skin and soft tissue infection (SSTI); vancomycin.