204 - Post-Liver Transplant Antimicrobial Use after the Expansion of a Pharmacist-Lead Antimicrobial Stewardship Program

Background: Antimicrobial stewardship programs (ASPs) allow for infectious diseases (ID)-trained practitioners to focus on timely and appropriate antimicrobial use. In December 2016, the ASP at Indiana University (IU) Health expanded from one ID pharmacist to three. The purpose of this study was to assess the impact of an expanding ASP on broad-spectrum antimicrobial use within post-liver transplant patients.

Methods: This was a retrospective, cross-sectional study. Data were collected from patients aged at least 18 years old that received a liver transplant either before or after the ASP expansion. Patients were excluded if they survived less than 72 hours after transplant, if they received a multivisceral transplant, or if there was an active infection prior to transplantation. The hypothesis of this study was that an expanded ASP leads to a reduction in days of therapy (DOT) per 1000 patient-days for a composite of broad-spectrum antimicrobial agents within this patient population.

Results: A total of 268 patients were included in this study. Of the patients that received at least one dose of the studied antimicrobial agents, the median (IQR) DOT per 1000 patient-days in the pre- and post-ASP expansion cohort was 174.4 (117.6 – 333.3) and 142.9 (62.5 – 257.5), respectively. This was statistically significant (difference 48.6, 95% CI 7.5 – 83.3). Specifically, the post-ASP expansion cohort used less meropenem (difference 197.8, 95% CI 66.3 – 451.6) and vancomycin (difference 57.6, 95% CI 2.2 – 132.2). The post-ASP expansion cohort also consulted ID for more patients (2 vs. 12 consults in the pre- and post-expansion group, respectively; p=0.011). Patient and graft survival one year after transplantation were similar between the two cohorts (p=0.540 and p=0.255, respectively).

Conclusion: An expanded ASP contributed to a reduction in broad-spectrum antimicrobial use in post-liver transplant patients without negatively impacting patient and graft survival one year post-transplantation. These data provide further evidence of ASP benefits within immunocompromised populations.