Risk factors for readmission among patients receiving outpatient parenteral antimicrobial therapy: a retrospective cohort study

Background In the Netherlands, home treatment with intravenous antimicrobial therapy is a relatively new concept. Although several studies have shown that outpatient parenteral antimicrobial therapy (OPAT) can be administered safely, people receiving antimicrobials at home remain at risk for adverse events, including readmission. Aim The aim of our retrospective study was to identify risk factors for readmission in patients discharged with OPAT. Method Patients who were at least 18 years or older, discharged with OPAT between January 2016-December 2018 were included. Variables that were collected consisted of baseline demographics, complications, readmission within 30 days and treatment failure. Multivariate logistic regression analysis was performed to identify risk factors for readmission. Results A total of 247 patients were included; the most common reason for OPAT was bone and joint infections (17%). Penicillin (37%), cephalosporin (26%) and vancomycin/aminoglycoside (15%) were the most commonly prescribed antimicrobials. Among patients receiving medication subject to therapeutic drug monitoring (i.e. aminoglycosides or vancomycin), 51% (19/37) received weekly therapeutic drug monitoring. Receiving aminoglycosides or vancomycin (adjusted OR 2.05; 95% CI 1.30-3.25, p < 0.05) and infection of prosthetic material (adjusted OR 2.92, 95% CI 1.11-7.65, p < 0.05) were independent risk factors associated with readmission. Conclusion Although patients receiving medication subject to therapeutic drug monitoring are at higher risk of readmission, only half of the patients discharged with aminoglycosides or vancomycin were monitored according to IDSA guidelines. A specialized team in charge of monitoring patients with OPAT is more likely to increase the rate of monitoring to prevent readmissions and complications.