Appropriateness of antibiotic selection at emergency department discharge and risk of 30-day adverse events in patients with acute exacerbation of COPD.

OBJECTIVE: To describe antibiotic prescribing patterns in acute exacerbations of chronic obstructive pulmonary disease (AECOPD) managed in emergency departments (EDs), assess the appropriateness of antibiotic selection according to Spanish guideline recommendations, and analyse its association with 30-day clinical outcomes. METHODS: Analysis derived from the multicentre retrospective EPOC-URG CAM registry (19 EDs in the Community of Madrid, 2022-2024), which included episodes of AECOPD. Antibiotic appropriateness was defined a priori according to national guideline recommendations. The primary outcome was the occurrence of an adverse event within 30 days, defined as recurrence of the exacerbation, ED revisit, hospitalisation, or death. The primary analysis was restricted to patients discharged directly from the ED with oral antibiotic treatment. Relative risks (RRs) were estimated using Poisson regression. RESULTS: A total of 4,136 episodes were analysed (mean age 74.5 ± 11.1 years; 68.3% male; 45.8% with a Charlson index ≥3). In the ED, 2,626 patients (63.5%) received antibiotics, with levofloxacin being the most frequently prescribed agent both in the ED (32.6%) and at discharge (39.3%). Patients' clinical profiles were very similar regardless of the antibiotic class prescribed at discharge. Of the 1,736 (42%) patients discharged directly from the ED, 987 (56.9%) received antibiotic treatment, and the prescription was considered inappropriate in 158 (16.0%). The incidence of 30-day adverse events was higher among patients receiving inappropriate antibiotic treatment (20.9% vs 13.3%; p=0.019). In the multivariable analysis, appropriate antibiotic treatment was the only modifiable factor independently associated with a lower risk of an adverse event (adjusted RR 0.59; 95% CI 0.41-0.85; p=0.004), whereas previous exacerbations (adjusted RR 1.80; 95% CI 1.15-2.83; p=0.010) and moderate exacerbation (adjusted RR 1.52; 95% CI 1.10-2.11; p=0.012) were associated with a higher risk. CONCLUSIONS: Antibiotic prescribing for AECOPD managed in the ED was characterised by a predominance of fluoroquinolones and limited individualisation according to patients' clinical profiles. Among patients discharged directly from the ED, antibiotic selection in accordance with national recommendations was independently associated with a reduced risk of a 30-day adverse event.