Discharge Delays and Costs Associated With Outpatient Parenteral Antimicrobial Therapy for Multidrug-Resistant Organisms: A Retrospective Cohort Study.

Background: Outpatient parenteral antimicrobial therapy (OPAT) coordination is challenging in multidrug-resistant organism (MDRO)-infected patients. The study purpose was to describe barriers and medication costs associated with OPAT utilizing therapies for MDRO. Methods: This was an institutional review board-approved, retrospective cohort of hospitalized, MDRO-infected adults medically stable for discharge (MSDC) with an intended OPAT for cefiderocol, ceftazidime/avibactam, ceftolozane/tazobactam, eravacycline, meropenem/vaborbactam, or tigecycline from 1 January 2017 through 31 March 2025. Cohorts included patients who received an intended or modified OPAT regimen, defined as transition to alternative intravenous (IV)/oral therapy, in-hospital completion of IV therapy, or in-hospital death. Secondary outcomes included post-MSDC medication costs, length of stay (LOS), and oral-switch therapy opportunities. Results: One hundred-twenty patients were included; 29% received a modified OPAT regimen. β-lactams were the most intended OPAT regimen (67%). Patients with a modified OPAT regimen had higher median (interquartile range [IQR]) medication costs ($4828 [$1209-$18 066] vs $1975 [$494-$4872], P < .001), more frequently experienced discharge delays ≥1 day (89% vs 66%, P = .011) and discharge referral disposition changes (40% vs 16%, P = .006), and had a prolonged median (IQR) LOS (20 [14-46] vs 13 [7-27] days, P  = .023), compared to those who received an intended OPAT regimen. Oral-switch therapy opportunities were identified in 40% of patients. After adjusting for Medicaid, referral disposition changes (adjusted odds ratio [aOR], 3.46 [95% confidence interval {CI}, 1.21-9.89) and initial β-lactam therapy (aOR, 4.08 [95% CI, 1.55-10.79]) were associated with an increased odds of receiving a modified OPAT regimen. Conclusions: Modified OPAT regimens are common and associated with increased costs, prolonged LOS, and discharge delays in MDRO-infected patients. These findings support the use of oral-switch therapy and improved care coordination.