Association between antibiotics and rehospitalization in patients with acute exacerbations of chronic obstructive pulmonary disease discharged from the emergency department

Background Patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are frequently discharged from the emergency department (ED) and treated with antibiotics. The role of antibiotics in the outpatient management of AECOPD is controversial and has never been studied in the ED setting. Methods We conducted a secondary analysis of prospectively collected data from the validation study of the Ottawa COPD Risk Scale. We included adult patients with AECOPD who were discharged from six tertiary care EDs in Canada over a two-year period and assessed rates of rehospitalization within 14 days of ED discharge. To examine the association between antibiotic treatment and rehospitalization, we performed multivariable logistic regression and propensity score-matched analyses. Results A total of 774 patients were included in the analysis. The mean age was 69.4 years, 388 patients (50.1%) were female, and 451 patients (58.3%) were discharged with antibiotics. Twenty-nine (6.4%) and 36 (11.1%) patients returned to hospital with admission in the antibiotic and no antibiotic groups, respectively (unadjusted OR 0.55; 95% CI 0.33-0.92); adjustment for prespecified baseline characteristics using logistic regression yielded OR 0.65; 95% CI 0.38-1.08. In the propensity score-matched analysis comprising of 197 matched pairs, 15 (7.6%) and 19 patients (9.6%) in the antibiotic and no antibiotic groups returned with admission, respectively (OR 0.69; 95% CI 0.29-1.62). Conclusion For patients with AECOPD discharged from the ED, we did not find an association between outpatient treatment with antibiotics and lower rates of rehospitalization after accounting for differences in baseline patient characteristics. However, the small sample size and low observed rate of the primary outcome created substantial risk of Type II error. Until further evidence is available, clinicians should continue prescribing antibiotics for patients with AECOPD based on clinical judgement and current practice guidelines.