title: Relationship between a clear-cut alternative noncardiac diagnosis and 30-day outcome in emergency department patients with chest pain.
abstract: BACKGROUND
  Accurate identification of patients with acute coronary syndromes (ACSs) in the emergency department (ED) remains problematic. Studies have not been able to identify a cohort of patients that are safe for immediate ED discharge; however, prior studies have not examined the utility of a clear-cut alternative noncardiac diagnosis.
  
  
  OBJECTIVE
  To compare the 30-day event rate in ED chest pain patients who were diagnosed with a clear-cut alternative noncardiac diagnosis with the 30-day event rate in the cohort of patients in whom a definitive diagnosis could not be made in the ED.
  
  
  METHODS
  This was a prospective cohort study of consecutive ED patients with potential ACS. Data included demographics, medical and cardiac history, laboratory and electrocardiogram results, and whether or not the treating physician ascribed the condition to a clear-cut alternative noncardiac diagnosis. The main outcome was death, acute myocardial infarction (AMI), or revascularization within 30 days, as determined by phone follow-up or medical record review.
  
  
  RESULTS
  The investigators enrolled 1,995 patients in the ED who had potential ACSs. Overall, 77 had a final hospital diagnosis of AMI (4%). Within 30 days, 73 patients received revascularization (4%), and 26 died (1%). There were 599 (30%) patients given a clear-cut alternative noncardiac diagnosis. Comparing the patients with a clear-cut alternative noncardiac diagnosis with those without an obvious noncardiac diagnosis, the presence of a clear-cut alternative noncardiac diagnosis was associated with a reduced risk of an in-hospital triple-composite endpoint (death, MI, and revascularization), with a risk ratio of 0.32 (95% confidence interval [CI] = 0.19 to 0.55) and 30-day triple-composite endpoint with a risk ratio of 0.45 (95% CI = 0.29 to 0.69); however, patients with a clear-cut alternative noncardiac diagnosis still had a 4% event rate at 30 days (95% CI = 2.4% to 5.6%).
  
  
  CONCLUSIONS
  In the ED chest pain patient, the presence of a clear-cut alternative noncardiac diagnosis reduces the likelihood of a composite outcome of death and cardiovascular events within 30 days. However, it does not reduce the event rate to an acceptable level to allow ED discharge of these patients.
authors.affiliation: Department of Emergency Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, USA. hollandj@uphs.upenn.edu
authors.forename: Judd E
authors.initials: JE
authors.lastname: Hollander
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Robey
authors.forename: Maureen R
authors.initials: MR
authors.lastname: Chase
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Brown
authors.forename: Kara E
authors.initials: KE
authors.lastname: Zogby
authors.forename: Frances S
authors.initials: FS
authors.lastname: Shofer
mesh_terms: D017677:Age Distribution; D015984:Causality; D002637:Chest Pain / Q000175:diagnosis* / Q000453:epidemiology*; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy; D009204:Myocardial Revascularization / Q000706:statistics & numerical data; D016017:Odds Ratio; D010414:Pennsylvania / Q000453:epidemiology; D011446:Prospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D016019:Survival Analysis