Assessing the utilization and impact of a newly established outpatient parenteral antimicrobial therapy (Opat) program

BACKGROUND: Outpatient parenteral antimicrobial therapy (OPAT) is a safe and effective alternative to hospitalization for many patients with infectious disease. The objective of this study was to describe the experience with a newly established formal OPAT program at a Canadian academic centre. METHODS: We conducted a retrospective cohort study including all patients referred to the OPAT clinic between July 2016 and June 2017 and a contemporary cohort of patients who received home parenteral therapy without clinic referral. A quasi-experimental design was used to assess the impact of the clinic on patient outcomes compared with a pre-intervention cohort of patients from 2012 to 2013. RESULTS: Between July 2016 and June 2017, 334 patients were referred to the OPAT clinic; 33% of the patients visited the emergency department (ED), and 21% required readmission within 60 days. Compared with the clinic patients, urinary tract infection diagnoses were more common among the 39 contemporary patients who were treated with home parenteral antibiotics without OPAT clinic referral (51% versus 4%, respectively; p < 0.001) and treatment durations were shorter (median 10 days versus 42 days; p < 0.001). Compared with a pre-intervention cohort, OPAT clinic implementation was associated with a trend toward decreased ED visits (33% versus 43%; p = 0.07). On multivariable analysis, this translated to an overall adjusted odds ratio of 0.64 (95% CI 0.40 to 1.04, p = 0.07) for readmission and ED visits. CONCLUSIONS: The OPAT clinic served a high volume of patients in its first year of operation and may be helpful in reducing unfavourable patient outcomes.