Emergency department case volume and patient outcomes in acute exacerbations of chronic obstructive pulmonary disease

Abstract

Objectives: The objective was to determine whether emergency department (ED) case volume of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is associated with patient outcomes in AECOPD.

Methods: The authors analyzed the 2007 Nationwide Emergency Department Sample (NEDS), the largest publicly available all-payer ED database in the United States. ED visits for AECOPD were identified with a principal diagnosis of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code 491.21. EDs were categorized into quartiles by ED case volume of AECOPD. The primary outcome measures were early inpatient mortality (within the first 3 days of admission) and hospital length of stay (LOS).

Results: The 2007 NEDS sample contained 126,045 ED visits for AECOPD from 946 U.S. EDs; 58% were hospitalized. Of these, the overall inpatient mortality rate was 2.0%, the early inpatient mortality 0.6%, and the median hospital LOS 4 days. Early inpatient mortality was lower in the highest-volume EDs (0.47%), compared with the lowest-volume EDs (1.13%). In a multivariable analysis adjusting for 37 patient and hospital characteristics, early inpatient mortality remained lower in patients admitted through the highest-volume EDs (adjusted odds ratios [ORs] = 0.51; 95% confidence interval [CI] = 0.32 to 0.82), compared with the lowest-volume EDs; however, the hospital LOS in the highest-volume EDs was slightly longer (adjusted difference in LOS = 0.53 day; 95% CI = 0.29 to 0.77). The volume threshold for reduced early mortality was approximately 200 cases per year.

Conclusions: ED patients who are hospitalized for AECOPD have an approximately 50% reduction in early inpatient mortality if they were admitted from an ED that handles a large volume of AECOPD cases.