title: The role of cardiac risk factor burden in diagnosing acute coronary syndromes in the emergency department setting.
abstract: OBJECTIVE
  We seek to determine whether cardiac risk factor burden (defined as the number of conventional cardiac risk factors present) is useful for the diagnosis of acute coronary syndromes in the emergency department (ED) setting.
  
  
  METHODS
  This was a post hoc analysis of the Internet Tracking Registry of Acute Coronary Syndromes (i*trACS) registry, which had 17,713 ED visits for suspected acute coronary syndromes. First visit for US patients who were not cocaine or amphetamine users, who did not leave against medical advice, and for whom ECG and demographic data were complete were included. Acute coronary syndrome was defined by 30-day revascularization, diagnostic-related group codes, or death within 30 days, with positive cardiac biomarkers at index hospitalization. Cardiac risk factors were diabetes, hypertension, smoking, hypercholesterolemia, and family history of coronary artery disease. Cardiac risk factor burden was defined as the number of risk factors present. Because multiple logistic regression analysis revealed that age modified the relationship between cardiac risk factor burden and acute coronary syndromes, a stratified analysis was performed for 3 age categories: younger than 40, 40 to 65, and older than 65 years. Positive likelihood ratios and negative likelihood ratios with their 95% confidence intervals (CIs) were calculated for each total risk factor cutoff.
  
  
  RESULTS
  Of 10,806 eligible patients, 871 (8.1%) had acute coronary syndromes. In patients younger than 40 years, having no risk factors had a negative likelihood ratio of 0.17 (95% CI 0.04 to 0.66), and having 4 or more risk factors had a positive likelihood ratio of 7.39 (95% CI 3.09 to 17.67). In patients between 40 and 65 years of age, having no risk factors had a negative likelihood ratio of 0.53 (95% CI 0.40 to 0.71), and having 4 or more risk factors had a positive likelihood ratio of 2.13 (95% CI 1.66 to 2.73). In patients older than 65 years, having no risk factors had a negative likelihood ratio of 0.96 (95% CI 0.74 to 1.23), and having 4 or more risk factors had a positive likelihood ratio of 1.09 (95% CI 0.64 to 1.62).
  
  
  CONCLUSIONS
  Cardiac risk factor burden has limited clinical value in diagnosing acute coronary syndromes in the ED setting, especially in patients older than 40 years.
authors.affiliation: Vanderbilt University Medical Center, Department of Emergency Medicine, Nashville, TN 37232-4700, USA. Jin.h.han@vanderbilt.edu
authors.forename: Jin H
authors.initials: JH
authors.lastname: Han
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Lindsell
authors.forename: Alan B
authors.initials: AB
authors.lastname: Storrow
authors.forename: Samuel
authors.initials: S
authors.lastname: Luber
authors.forename: James W
authors.initials: JW
authors.lastname: Hoekstra
authors.forename: Judd E
authors.initials: JE
authors.lastname: Hollander
authors.forename: W Franklin
authors.initials: WF
authors.lastname: Peacock
authors.forename: Charles V
authors.initials: CV
authors.lastname: Pollack
authors.forename: W Brian
authors.initials: WB
authors.lastname: Gibler
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D015415:Biomarkers; D003327:Coronary Disease / Q000175:diagnosis* / Q000209:etiology; D003953:Diagnosis-Related Groups / Q000145:classification / Q000458:organization & administration; D004562:Electrocardiography; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D012372:ROC Curve; D012042:Registries; D012307:Risk Factors; D017678:Sex Distribution
chemical_list: D015415:Biomarkers