Michael E Rezaee,1 Charlotte E Ward,2,3 Bonita Nuanez,1 Daniel A Rezaee,4 Jeffrey Ditkoff,1,5 Alexandra Halalau1,6 1Oakland University William Beaumont School of Medicine, Rochester, MI, 2Center for Healthcare Studies, Feinberg School of Medicine, Northwestern University, 3Center for Health Statistics, University of Chicago, Chicago, IL, 4Primary Care, Brigham and Women’s Hospital, Boston, MA, 5Emergency Medicine, 6Internal Medicine, Beaumont Health, Royal Oak, MI, USA Background: Thirty-day readmission in COPD is common and costly, but potentially preventable. The emergency department (ED) may be a setting for COPD readmission reduction efforts.Objective: To better understand COPD readmission through the ED, ascertain factors associated with 30-day readmission through the ED, and identify subgroups of patients with COPD for readmission reduction interventions.Patients and methods: A retrospective cohort study was conducted from January 2009 to September 2015 in patients with COPD of age ≥18 years. Electronic health record data were abstracted for information available to admitting providers in the ED. The primary outcome was readmission through the ED within 30 days of discharge from an index admission for COPD. Logistic regression was used to examine the relationship between potential risk factors and 30-day readmission.Results: The study involved 1,574 patients who presented to the ED within 30 days on an index admission for COPD. Of these, 82.2% were readmitted through the ED. Charlson score (odds ratio [OR]: 3.6; 95% CI: 2.9–4.4), a chief complaint of breathing difficulty (OR: 1.6; 95% CI: 1.1–2.6), outpatient utilization of albuterol (OR: 4.1; 95% CI: 2.6–6.4), fluticasone/salmeterol (OR: 2.3; 95% CI: 1.3–4.2), inhaled steroids (OR: 3.8; 95% CI: 1.3–10.7), and tiotropium (OR: 1.8; 95% CI: 1.0–3.2), as well as arterial blood gas (OR: 4.4; 95% CI: 1.3–15.1) and B-type natriuretic peptide (OR: 2.2; 95% CI: 1.4–3.5) testing in the ED were associated with readmission (c-statistic =0.936). Seventeen-point-eight percent of patients with COPD presented to the ED and were discharged home; 56% presented with a complaint other than breathing difficulty; and 16% of those readmitted for breathing difficulty had a length of stay <48 hours.Conclusion: Intensive outpatient monitoring, evaluation, and follow-up after discharge are needed to help prevent re-presentation to the ED, as practically all patients with COPD who re-present to the ED within 30 days are readmitted to the hospital and for a variety of clinical complaints. Among those patients with COPD who present with breathing difficulty, improved decision support algorithms and alternative management strategies are needed to identify and intervene on the subgroup of patients who require <48-hour length of stay. Keywords: COPD, readmission, emergency department, dyspnea, length of stay, observation study, epidemiology, hospital admission