Emergency department case volume and patient outcomes in acute exacerbations of chronic obstructive pulmonary disease.
OBJECTIVE
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.
Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas School of Public Health, Houston, TX, USA. cltsai@post.harvard.edu
Chu-Lin
CL
Tsai
George L
GL
Delclos
Carlos A
CA
Camargo
D000208:Acute Disease; D000368:Aged; D015331:Cohort Studies; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology* / Q000401:mortality; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology