Risk Factors for Hospital Readmission Following Outpatient Parenteral Antimicrobial Therapy (OPAT)

A main goal of outpatient parenteral antibiotic therapy (OPAT) is to streamline patient care and minimize time spent in the inpatient hospital setting. The identification of characteristics of patients who return to the hospital after being discharged on OPAT may identify modifiable steps that can be taken to reduce risk of hospital readmission as a practice improvement strategy.

We performed a retrospective analysis of adult patients prescribed OPAT for ≥ 14 days prescribed by infectious disease consultation for non-urinary tract infections (non-UTI). We compared characteristics including demographics, sites of infection, microbiology, and antimicrobial therapy prescribed.

Of 233 adult OPAT patients with non-UTI infections receiving ID consultation, 61 (26%) were readmitted to the hospital (60 days), of which 37 (60%) were due to treatment failure. Ceftriaxone once daily was the most prescribed antimicrobial therapy. Microbiology and infection sites were similar between the two groups. Obesity (body mass index, BMI > 30 kg/m²) was more frequent among readmitted patients versus those not readmitted (odds ratio 3.6, 95% confidence interval 1.9-6.5, p < 0.0001). Polymicrobial infections were significantly more frequent among the readmitted group compared with the non-readmitted group (odds ratio 3.2, 95% confidence interval 1.7-6.0, p = 0.0004).

Patients with obesity may not be receiving sufficient antimicrobial exposure with standard antibiotic dosing regimens, particularly with ceftriaxone. Antibiotic dosing in patients with obesity requires further study and optimization, particularly with cephalosporins.