title: Evaluation of a Prediction Model for the Development of Atrial Fibrillation in a Repository of Electronic Medical Records.
abstract: OBJECTIVE
  Atrial fibrillation (AF) contributes to substantial morbidity, mortality, and health care expenditures. Accurate prediction of incident AF would enhance AF management and potentially improve patient outcomes.
  
  
  OBJECTIVE
  To validate the AF risk prediction model originally developed by the Cohorts for Heart and Aging Research in Genomic Epidemiology-Atrial Fibrillation (CHARGE-AF) investigators using a large repository of electronic medical records (EMRs).
  
  
  METHODS
  In this prediction model study, deidentified EMRs of 33 494 individuals 40 years or older who were white or African American and had no history of AF were reviewed and analyzed. The participants were followed up in the internal medicine outpatient clinics at Vanderbilt University Medical Center for incident AF from December 31, 2005, until December 31, 2010. Adjusting for differences in baseline hazard, the CHARGE-AF Cox proportional hazards model regression coefficients were applied to the EMR cohort. A simple version of the model with no echocardiographic variables was also evaluated. Data were analyzed from October 31, 2013, to January 31, 2014.
  
  
  METHODS
  Incident AF. Predictors in the model included age, race, height, weight, systolic and diastolic blood pressure, treatment for hypertension, smoking status, type 2 diabetes, heart failure, history of myocardial infarction, left ventricular hypertrophy, and PR interval.
  
  
  RESULTS
  Among the 33 494 participants, the median age was 57 (interquartile range, 49-67) years; 57% of patients were women, 43% were men, 85.7% were white, and 14.3% were African American. During the mean (SD) follow-up of 4.8 (0.9) years, 2455 individuals (7.3%) developed AF. Both models had poor calibration in the EMR cohort, with underprediction of AF among low-risk individuals and overprediction of AF among high-risk individuals (10th and 90th percentiles for predicted probability of incident AF, 0.005 and 0.179, respectively). The full CHARGE-AF model had a C index of 0.708 (95% CI, 0.699-0.718) in our cohort. The simple model had similar discrimination (C index, 0.709; 95% CI, 0.699-0.718; P = .70 for difference between models).
  
  
  CONCLUSIONS
  Despite reasonable discrimination, the CHARGE-AF models showed poor calibration in this EMR cohort. This study highlights the difficulties of applying a risk model derived from prospective cohort studies to an EMR cohort and suggests that these AF risk prediction models be used with caution in the EMR setting. Future risk models may need to be developed and validated within EMR cohorts.
authors.affiliation: Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Kolek
authors.affiliation: Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Graves
authors.affiliation: Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Meng
authors.initials: M
authors.lastname: Xu
authors.affiliation: Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Aihua
authors.initials: A
authors.lastname: Bian
authors.affiliation: Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Pedro Luis
authors.initials: PL
authors.lastname: Teixeira
authors.affiliation: Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: M Benjamin
authors.initials: MB
authors.lastname: Shoemaker
authors.affiliation: Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Babar
authors.initials: B
authors.lastname: Parvez
authors.affiliation: School of Biomedical Informatics, University of Texas Health Science Center at Houston.
authors.forename: Hua
authors.initials: H
authors.lastname: Xu
authors.affiliation: Department of Epidemiology, University of Washington, Seattle.
authors.forename: Susan R
authors.initials: SR
authors.lastname: Heckbert
authors.affiliation: Cardiac Arrhythmia Service, Massachusetts General Hospital, Boston.
authors.forename: Patrick T
authors.initials: PT
authors.lastname: Ellinor
authors.affiliation: Framingham Heart Study, National Heart Lung and Blood Institute and Boston University, Framingham, Massachusetts8Department of Medicine, Boston University School of Medicine, Boston, Massachusetts.
authors.forename: Emelia J
authors.initials: EJ
authors.lastname: Benjamin
authors.affiliation: Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Alonso
authors.affiliation: Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Denny
authors.affiliation: Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee10Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Karel G M
authors.initials: KG
authors.lastname: Moons
authors.affiliation: Department of Biostatistics, Osaka University, Suita, Japan.
authors.forename: Ayumi K
authors.initials: AK
authors.lastname: Shintani
authors.affiliation: Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Frank E
authors.initials: FE
authors.lastname: Harrell
authors.affiliation: Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee.
authors.forename: Dan M
authors.initials: DM
authors.lastname: Roden
authors.affiliation: Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee12Division of Cardiology, University of Illinois at Chicago.
authors.forename: Dawood
authors.initials: D
authors.lastname: Darbar