title: Validation of an atrial fibrillation risk algorithm in whites and African Americans.
abstract: BACKGROUND
  We sought to validate a recently published risk algorithm for incident atrial fibrillation (AF) in independent cohorts and other racial groups.
  
  
  METHODS
  We evaluated the performance of a Framingham Heart Study (FHS)-derived risk algorithm modified for 5-year incidence of AF in the FHS (n = 4764 participants) and 2 geographically and racially diverse cohorts in the age range 45 to 95 years: AGES (the Age, Gene/Environment Susceptibility-Reykjavik Study) (n = 4238) and CHS (the Cardiovascular Health Study) (n = 5410, of whom 874 [16.2%] were African Americans). The risk algorithm included age, sex, body mass index, systolic blood pressure, electrocardiographic PR interval, hypertension treatment, and heart failure.
  
  
  RESULTS
  We found 1359 incident AF events in 100 074 person-years of follow-up. Unadjusted 5-year event rates differed by cohort (AGES, 12.8 cases/1000 person-years; CHS whites, 22.7 cases/1000 person-years; and FHS, 4.5 cases/1000 person-years) and by race (CHS African Americans, 18.4 cases/1000 person-years). The strongest risk factors in all samples were age and heart failure. The relative risks for incident AF associated with risk factors were comparable across cohorts and race groups. After recalibration for baseline incidence and risk factor distribution, the Framingham algorithm, reported in C statistic, performed reasonably well in all samples: AGES, 0.67 (95% confidence interval [CI], 0.64-0.71); CHS whites, 0.68 (95% CI, 0.66-0.70); and CHS African Americans, 0.66 (95% CI, 0.61-0.71). Risk factors combined in the algorithm explained between 47.0% (AGES) and 63.6% (FHS) of the population-attributable risk.
  
  
  CONCLUSIONS
  Risk of incident AF in community-dwelling whites and African Americans can be assessed reliably by routinely available and potentially modifiable clinical variables. Seven risk factors accounted for up to 64% of risk.
authors.affiliation: Department of Medicine, Johannes Gutenberg University, Mainz, Germany.
authors.forename: Renate B
authors.initials: RB
authors.lastname: Schnabel
authors.forename: Thor
authors.initials: T
authors.lastname: Aspelund
authors.forename: Guo
authors.initials: G
authors.lastname: Li
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Sullivan
authors.forename: Astrid
authors.initials: A
authors.lastname: Suchy-Dicey
authors.forename: Tamara B
authors.initials: TB
authors.lastname: Harris
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Pencina
authors.forename: Ralph B
authors.initials: RB
authors.lastname: D'Agostino
authors.forename: Daniel
authors.initials: D
authors.lastname: Levy
authors.forename: William B
authors.initials: WB
authors.lastname: Kannel
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Wang
authors.forename: Richard A
authors.initials: RA
authors.lastname: Kronmal
authors.forename: Philip A
authors.initials: PA
authors.lastname: Wolf
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Burke
authors.forename: Lenore J
authors.initials: LJ
authors.lastname: Launer
authors.forename: Ramachandran S
authors.initials: RS
authors.lastname: Vasan
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Psaty
authors.forename: Emelia J
authors.initials: EJ
authors.lastname: Benjamin
authors.forename: Vilmundur
authors.initials: V
authors.lastname: Gudnason
authors.forename: Susan R
authors.initials: SR
authors.lastname: Heckbert
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001281:Atrial Fibrillation / Q000453:epidemiology*; D044383:Black People; D001794:Blood Pressure; D015992:Body Mass Index; D015331:Cohort Studies; D004562:Electrocardiography; D005060:Europe / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000453:epidemiology; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000628:therapy; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012307:Risk Factors; D012737:Sex Factors; D013599:Systole; D014481:United States / Q000453:epidemiology; D044465:White People; D001741:Black or African American