Identifying Stewardship Opportunities for OPAT Patients Upon Readmission

The use of outpatient parenteral antimicrobial therapy (OPAT) continued in a quarter of hospital readmissions, according to a new Open Forum Infectious Diseases report. The study authors believe this indicates an opportunity for collaboration between infectious disease services, antibiotic stewardship programs (ASPs), and OPAT teams.

OPAT is designed to allow patients undergoing long-course intravenous antibiotic treatment for infectious to avoid lengthy hospital stays. About 1 in 1000 people receive OPAT annually in the United States, though antimicrobial therapies are sometimes broadened upon hospital discharge for cost-saving initiatives or because broader antimicrobials may be easier to administer in the outpatient setting.

Ertapenem and daptomycin are once-daily regiments with broader coverage, but they have higher direct drug costs, the study authors explained.

Investigators conducted a retrospective review of adults enrolled in OPAT and discharged on ertapenem or daptomycin for ease of once-daily administration (EOA). The patients were all treated at

Rachel Britt, PharmD

the Beth Israel Deaconess Medical Center in Boston between 2014 and 2017. The investigators did not find much literature describing continuation of EOA regimens after hospital readmission during OPAT, study author Rachel Britt, PharmD, told Contagion®.

They identified their study subjects using the terms “convenience” or “EOA” in OPAT notes or when the patients were switched to ertapenem or daptomycin upon OPAT enrollment. The study authors’ aim was to analyze the percentage of patients readmitted during or subsequent to their OPAT course that maintained an EOA regimen. They also examined the inpatient therapy cost, the rates of Clostridioides difficile (C diff) infection, and adverse events throughout the study period.

The study authors found that of 188 patients receiving an OPAT EOA regimen, 71 were readmitted (within the investigators’ defined period of 90 days). That made up 113 unique readmissions and 77 unique OPAT courses, they determined. Ertapenem was used more frequently for EOA (69%) compared to daptomycin (27%), though in 4% of cases both were used, the study authors reported.

Those who were readmitted were mostly males (71%), of older age (median 57 years), and a median weight of 83 kg, the study authors wrote. A majority of these patients received OPAT at home (89%) compared to an extended care facility. Allergies to antimicrobial agents accounted for 26% of readmissions (most commonly penicillin and sulfonamide).

The most common reason for therapy was osteomyelitis, followed by intra-abdominal infection, empyema, prosthetic joint infection, diabetic foot infection, acute bacterial skin and soft tissue infection, urinary tract infection, and central-line associated bloodstream infection.

“We do believe that our findings reflect practices in other institutions that treat OPAT patients and would expect the rate of OPAT EOA regimen continuation and number of inpatient doses of the OPAT EOA agent to be higher in institutions that do not utilize a preauthorization strategy as part of their ASPs,” Britt told Contagion®. “In an era of increasing antimicrobial resistance and OPAT, our findings identify a potential area for increased ASP attention and collaboration with OPAT teams to determine optimal inpatient antimicrobial regimens for readmitted OPAT patients.”

EOA regimens were continued in 27% of hospital readmissions: one-quarter of those were preplanned by the medical surgical team, and about one-third were related to the OPAT course, either worsening infection or an adverse drug event, the investigators said.

The median length of stay for all readmissions was 5 days. The study authors determined the inpatient cost of EOA regimens was $15,644, or $150 per patient. However, if patients had continued on their pre-OPAT inpatient regiment upon readmission, they said, the cost would have been $3440 or about $83 per patient.

The study authors discovered adverse events reported in about 12% of all cases, including fever and seizures among patients administered ertapenem. C diff infections occurred in 7% of readmissions (9% for the daptomycin group and 6% in the ertapenem group).

The investigators think it’s possible that their findings may prompt admitting providers that encounter patients with this need to be thorough in reading OPAT notes and infectious disease treatment history, so they can make thoughtful and purposeful decisions about patient treatments with antimicrobial agents.

“ASP, inpatient ID, and OPAT teams should discuss these situations preemptively to create plans and protocols that address the goals and needs of each team and maintain open lines of communication in individual patient cases,” Britt concluded.