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

Abstract 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.