title: ED visit volume and quality of care in acute exacerbations of chronic obstructive pulmonary disease.
abstract: OBJECTIVE
  The purpose of this study is to determine whether emergency department (ED) visit volume is associated with ED quality of care in patients with acute exacerbations of chronic obstructive pulmonary disease (COPD).
  
  
  METHODS
  We performed a prospective multicenter cohort study involving 29 EDs in the United States and Canada. Using a standard protocol, we interviewed consecutive ED patients with COPD exacerbation, reviewed their charts, and completed a 2-week telephone follow-up. The associations between ED visit volume and quality of care (process and outcome measures) were examined at both the ED and patient levels.
  
  
  RESULTS
  After adjustment for patient mix in the multivariable analyses, chest radiography was less frequent among patients with COPD exacerbations in the low-volume (odds ratio [OR], 0.2; 95% confidence interval [CI], 0.1-0.4) and high-volume EDs (OR, 0.1; 95% CI, 0.05-0.5), with medium-volume EDs as the reference. Arterial blood gas testing was less frequent in the low-volume EDs (OR, 0.1; 95% CI, 0.02-0.8). Medication use was similar across volume tertiles. With respect to outcome measures, patients in high-volume EDs were more likely to be discharged (OR, 4.2; 95% CI, 2.2-7.7) and to report ongoing exacerbation at a 2-week follow-up (OR, 1.9; 95% CI, 1.02-3.5).
  
  
  CONCLUSIONS
  Traditional positive volume-quality relationships did not apply to emergency care of COPD exacerbation. High-volume EDs used less guideline-recommended diagnostic procedures, had a higher admission threshold, and had a worse short-term patient-centered outcome.
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA. ctsai2@partners.org
authors.forename: Chu-Lin
authors.initials: CL
authors.lastname: Tsai
authors.forename: Brian H
authors.initials: BH
authors.lastname: Rowe
authors.forename: Rita K
authors.initials: RK
authors.lastname: Cydulka
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
mesh_terms: D000368:Aged; D001509:Bed Occupancy; D002170:Canada; D015331:Cohort Studies; D004632:Emergency Medical Services / Q000458:organization & administration*; D005260:Female; D019983:Guideline Adherence; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D010043:Outcome and Process Assessment, Health Care; D017060:Patient Satisfaction; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis* / Q000628:therapy*; D014481:United States