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

## TL;DR

This study shows that many patients with drug-resistant infections don't get their planned outpatient antibiotic treatment, leading to higher costs and longer hospital stays.

## Contribution

The study identifies transition-of-care barriers and quantifies their impact on costs and hospital length of stay for multidrug-resistant organism patients receiving OPAT.

## Key findings

- 29% of patients received a modified OPAT regimen instead of the intended therapy.
- Modified OPAT regimens were associated with higher medication costs and longer hospital stays.
- Oral-switch therapy opportunities were identified in 40% of patients.

## Abstract

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.

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.

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.

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.

This study found that one-third of patients infected with multidrug-resistant organisms who require outpatient parenteral antimicrobial therapy with novel agents do not receive intended therapy due to transition of care barriers. This is associated with significantly higher costs and longer hospital stays.