Outpatient Antibiotic Treatment Outcomes in Vulnerable Populations: Homeless and Current Injection Drug Users

Abstract

Background. Life-threatening infections such as endocarditis and osteomyelitis are difficult to treat and often require long courses of intravenous (IV) antibiotics. For homeless or injection drug users (IDU), creating an outpatient antibiotic treatment plan can be challenging. We examined patient outcomes of our outpatient parenteral antimicrobial therapy (OPAT) program, with a specific focus on high-risk populations -the homeless and IDU-to evaluate program function and identify target areas for improvement around transitions of care. Methods. We identified hospitalized patients receiving IV antibiotics with a peripherally inserted central line. They were enrolled in OPAT if IV antibiotics were continued upon discharge. Information was entered using REDCap, a data-reporting tool linked to the University of Washington's Clinical Data Repository, which collects information from the electronic medical record. Key demographics, length of hospital stay (LOS), and 30-day hospital readmissions were abstracted. Data on homelessness and substance abuse were manually entered. Results. We identified 688 OPAT episodes from 1 January 2015 to 30 April 2016 (table). Median LOS (days) was longer in the homeless (11.3) and IDU (12.6) than the overall OPAT population (10.4). Readmission rates were higher among the homeless (29%) and current IDU (28%) than the overall OPAT population (20%). Compared to neither homeless nor current IDU, LOS was 2.1 days longer and readmission rates were 2 times higher in the homeless and current IDU. Conclusion. The homeless and current IDU comprise a significant portion of the OPAT population and contribute to longer LOS and higher rates of hospital readmission. We plan to use these data to target future interventions towards high-risk groups to improve outpatient care coordination and clinical outcomes.