title: Validation of the Risk Estimator Decision Aid for Atrial Fibrillation (RED-AF) for predicting 30-day adverse events in emergency department patients with atrial fibrillation.
abstract: OBJECTIVE
  In the United States, nearly 70% of emergency department (ED) visits for atrial fibrillation result in hospitalization. The incidence of serious 30-day adverse events after an ED evaluation for atrial fibrillation remains low. This study's goal was to prospectively validate our previously reported Risk Estimator Decision Aid for Atrial Fibrillation (RED-AF) model for estimating a patient's risk of experiencing a 30-day adverse event.
  
  
  METHODS
  This was a prospective cohort study, which enrolled a convenience sample of ED patients presenting with atrial fibrillation. RED-AF, previously derived from a retrospective cohort of 832 patients, assigns points according to age, sex, coexisting disease (eg, heart failure, hypertension, chronic obstructive pulmonary disease), smoking, home medications (eg, β-blocker, diuretic), physical examination findings (eg, dyspnea, palpitations, peripheral edema), and adequacy of ED ventricular rate control. Primary outcome was occurrence of greater than or equal to 1 atrial fibrillation-related adverse outcome (ED visits, rehospitalization, cardiovascular complications, death) within 30 days. We identified a clinically relevant threshold and measured RED-AF's performance in this prospective cohort, assessing its calibration, discrimination, and diagnostic accuracy.
  
  
  RESULTS
  The study enrolled 497 patients between June 2010 and February 2013. Of these, 120 (24%) had greater than or equal to 1 adverse event within 30 days. A RED-AF score of 87 was identified as an optimal threshold, resulting in sensitivity and specificity of 96% (95% confidence interval [CI] 91% to 98%) and 19% (95% CI 15% to 23%), respectively. Positive and negative predictive values were 27% (95% CI 23% to 32%) and 93% (95% CI 85% to 97%), respectively. The c statistic for RED-AF was 0.65 (95% CI 0.59 to 0.71).
  
  
  CONCLUSIONS
  In this separate validation cohort, RED-AF performed moderately well and similar to the original derivation cohort for identifying the risk of short-term atrial fibrillation-related adverse events in ED patients receiving a diagnosis of atrial fibrillation.
authors.affiliation: Department of Emergency Medicine, Vanderbilt University School of Medicine, Nashville, TN. Electronic address: tyler.barrett@vanderbilt.edu.
authors.forename: Tyler W
authors.initials: TW
authors.lastname: Barrett
authors.affiliation: Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN.
authors.forename: Cathy A
authors.initials: CA
authors.lastname: Jenkins
authors.affiliation: Department of Emergency Medicine, Vanderbilt University School of Medicine, Nashville, TN.
authors.forename: Wesley H
authors.initials: WH
authors.lastname: Self
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000150:complications* / Q000401:mortality; D003661:Decision Support Techniques; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods / Q000592:standards; D012307:Risk Factors; D012680:Sensitivity and Specificity; D055815:Young Adult