Clinical and operational factors associated with treatment duration for cellulitis in outpatient parenteral antimicrobial therapy (OPAT).

This study aims to identify factors associated with duration of intravenous (IV) and follow-on oral antibiotic therapy for cellulitis in patients treated through outpatient parenteral antimicrobial therapy (OPAT). A retrospective review of episodes of cellulitis treated over a year (January 2018-January 2019) at a large teaching hospital in Sheffield, UK. Overall, 292 OPAT episodes of cellulitis were reviewed. The mean durations of IV therapy and follow-on oral antibiotics were 5.3 days (range 1-32 days) and 6.1 days (range 2-17 days), respectively. Age, peak C-reactive protein and frequency of medical assessments during OPAT were independently associated with longer duration of IV therapy. Senior clinicians were likely to prescribe shorter courses of follow-on oral antibiotics. IV to oral conversion was more likely to occur on the first day of the work week. Our findings suggest that clinical and OPAT-related factors can influence early conversion to oral antibiotic therapy.