1025. Utility of a Risk Assessment Model in Predicting 30-day Unplanned Hospital Readmission in Adult Patients Receiving Outpatient Parenteral Antimicrobial Therapy

Abstract Background Outpatient parenteral antimicrobial therapy (OPAT) is used for patients that require prolonged durations of intravenous (IV) antimicrobials and who are healthy enough to receive the medications in the outpatient setting. While OPAT is both efficacious and cost-effective, hospital readmission rates are high. Durojaiye and colleagues in the UK developed a 30-day unplanned readmission risk prediction model for OPAT patients. Given differences in patient mix and methods of OPAT delivery, we validated the established risk assessment model for Duke University Health System (DUHS) patients receiving OPAT. Methods A retrospective review of 606 OPAT episodes of adult patients who were enrolled in the DUHS OPAT program between July 1, 2019 and February 1, 2020 was conducted. The review captured the 6 risk predictors of the established model: age, Charlson Comorbidity Score, number of admissions in the preceding 12 months, concurrent receipt of more than one IV antimicrobial agent, type of infection, and mode of OPAT delivery. Additional risk predictors were captured: aminoglycoside use, vancomycin use, OPAT delivery in a skilled nursing facility, and history of IV drug abuse. The discriminative ability of the model to predict 30-day unplanned readmission as well as 30-day OPAT-related unplanned readmission was validated with the collected data using scaled Brier score, Hosmer-Lemeshow goodness-of-fit, and area under the receiver operating curve. A logistic regression model fitted with the additional risk factors was conducted to determine their impact on the model. Results When comparing DUHS OPAT patients with those of the UK model, DUHS patients were sicker (mean Charlson Comorbidity Score 3 vs 1), were treated for deeper seated infections, and received OPAT through different modes. Overall the 30-day unplanned readmission rate was 20.0% (94/470), with 59.5% of those being OPAT-related. The UK model was unable to discriminate between patients with readmission and those without, both overall and OPAT-related. The additional risk factors were also non-significant between the groups and the updated model could not predict 30-day readmission risk. Conclusion The UK 30-day unplanned hospital readmission model did not predict patient risk of readmission for the Duke OPAT population. Disclosures Richard H. Drew, PharmD MS, American College of Clinical Pharmacists: Publication royalties|Takeda: Advisor/Consultant|UpToDate: publication royalties.