Evaluation of Inpatient Antimicrobial Regimens for Readmitted Outpatient Parenteral Antimicrobial Therapy Patients Receiving Daptomycin or Ertapenem for Ease of Administration

Background. Outpatient parenteral antimicrobial therapy (OPAT) allows for long-course intravenous treatment of infections without lengthy hospital stays. Upon discharge, antimicrobial therapy may be broadened for "ease" of once-daily administration (EOA). Patients requiring subsequent readmission can be tailored to pre-OPAT regimens to minimize adverse effects. This study assessed continuation of EOA regimens upon hospital readmission during or immediately after OPAT. Methods. This was a retrospective review of adults enrolled in OPAT and discharged on ertapenem or daptomycin for EOA, defined by the terms "convenience" or "EOA" in OPAT notes or by switching to ertapenem or daptomycin upon OPAT enrollment despite adequate therapy with narrower-spectrum agents. The primary outcome was the percentage of patients readmitted during or after their OPAT course and maintained on an EOA regimen. Secondary outcomes included inpatient therapy cost, rates of Clostridioides difficile infection, and adverse events. Results. Of 188 patients receiving an OPAT EOA regimen, 71 were readmitted, representing 113 unique readmissions. Patients were mostly males (81%) aged 57 years. The EOA regimens were continued in 27% of hospital readmissions. The Infectious Diseases (ID) team was consulted in 48% of readmissions, and the Antimicrobial Stewardship Program (ASP) intervened in 26%. Combined, this resulted in de-escalation in 28% of cases. Clostridioides difficile infections and adverse events occurred in 7% and 12% of readmissions, respectively. The median acquisition cost of inpatient EOA regimens was $150 per readmission. Conclusions. The OPAT EOA regimens were continued in 27% of hospital readmissions indicating a role for improved indication documentation and collaboration between ID services, ASPs, and OPAT teams.