Optimizing antimicrobial stewardship indicators in the emergency department through the application of days of...

Antimicrobial prescribing in the emergency department is influenced by short stays, diagnostic uncertainty, and frequent empirical treatment initiation, which complicates the interpretation of antimicrobial use indicators. Days of antibiotic spectrum coverage (DASC) integrates duration and spectrum breadth and may provide complementary information for antimicrobial-use surveillance and stewardship.

Retrospective observational study using aggregated quarterly data from adult ED episodes (January 2021-December 2025). Global antimicrobial use was assessed using Defined Daily Dose (DDD)/100 visits, DDD/100 patient-days, Days of Therapy (DOT)/100 visits, proportion of patients receiving antimicrobials, DASC/100 visits, and DASC/DOT. Trends were analyzed using temporal trend analysis. The main therapeutic groups were evaluated according to their contributions to the total DOT and DASC.

During the study period, global antimicrobial consumption decreased for most indicators. DDD/100 visits decreased from 11.28 in 2021 to 8.85 in 2025, DOT/100 visits from 19.08 to 13.31, and the proportion of patients receiving antimicrobials from 12.3% to 9.4%. DASC/100 visits decreased from 132.10 to 94.49 (28.5%). In contrast, DASC/DOT remained stable, with a slight increase from 6.92 to 7.10. Penicillins combined with beta-lactamase inhibitors were the largest contributors to DASC, followed by third-generation cephalosporins, fluoroquinolones, and carbapenems. The reduction in total DASC was mainly driven by decreases in third-generation cephalosporins, fluoroquinolones, metronidazole, and carbapenem exposure, whereas macrolide exposure increased over time.

Metrics based on the DASC offer complementary insights to DDD and DOT and may assist antimicrobial stewardship programs in identifying ongoing broad-spectrum prescriptions in emergency care.