Leveling Up: Evaluation of IV v. PO Linezolid Utilization and Cost after an Antimicrobial Stewardship Program Revision of IV to PO Conversion Criteria within a Healthcare System

Abstract

The CDC’s Core Elements of an Antimicrobial Stewardship Program (ASP) lists intravenous (IV) to oral (PO) conversion as an important pharmacy-based intervention. However, despite the existence of a pharmacist-driven IV to PO conversion protocol, conversion rates within our healthcare system remained low. We aimed to evaluate the impact of a revision to the current conversion protocol on conversion rates, using linezolid as a marker due to its high PO bioavailability and high IV cost. This retrospective, observational study was conducted within a healthcare system composed of five adult acute care facilities. The conversion eligibility criteria were evaluated and revised on 30 November 2021. The pre-intervention period started February 2021 and ended November 2021. The post-intervention period was December 2021 to March 2022. The primary objective of this study was to establish if there was a difference in PO linezolid utilization reported as days of therapy per 1000 days present (DOT/1000 DP) between the pre- and post-intervention periods. IV linezolid utilization and cost savings were investigated as secondary objectives. The average DOT/1000 DP for IV linezolid decreased from 52.1 to 35.4 in the pre- and post-intervention periods, respectively (p p p p p = 0.03) This study shows the significant impact that an ASP intervention had on IV to PO conversion rates and subsequent spend. By revising criteria for IV to PO conversion, tracking and reporting results, and educating pharmacists, this led to significantly more PO linezolid use and reduced the overall cost in a large healthcare system.

Keywords

• IV to PO
• enteral
• parenteral
• linezolid
• cost savings
• antimicrobial stewardship