The impact of time to first antimicrobial dose on length of stay and 30-day hospital readmission in patients with lower limb cellulitis.

Abstract Objectives : There have been efforts to promote timely antimicrobial administration for patients with sepsis, but the importance for other infections is uncertain. This study analysed whether time to first antimicrobial dose (TFAD) in patients with lower limb cellulitis influenced outcome measures such as length of acute hospital stay (LOS) and 30-day hospital readmission rates for cellulitis. Methods : Medical records of patients admitted with lower limb cellulitis or erysipelas over a 15-month period (1 May 2019 to 30 November 2019 & 1 March 2020 to 31 October 2020) were reviewed. Patients requiring admission to intensive care (ICU) were excluded. The TFAD was the difference (in minutes) between the emergency department triage time and the time that the antimicrobial was first recorded as administered. Analysis included log-transformed linear regression (for LOS) and logistic regression (for 30-day readmission with cellulitis), controlling for confounders where possible. Results : The study included 282 patients with lower limb cellulitis. The median TFAD was 177 minutes (IQR 98-290). Linear regression suggested a weak association between TFAD and LOS (p=0.05, adjusted R2= 1%), which was non-significant after adjusting for confounders (p=0.18). There were too few patients readmitted within 30-days with cellulitis to analyse meaningfully. Conclusions : After controlling for confounders, no association between increased TFAD and an increased acute LOS was identified for patients with lower limb cellulitis who did not require ICU admission (i.e. without septic shock). Conclusions could not be made for 30-day readmission rates for cellulitis.