Validation of an Atrial Fibrillation Risk Algorithm in Whites and African Americans | Atrial Fibrillation | JAMA Internal Medicine | JAMA Network
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Original Investigation
November 22, 2010

Validation of an Atrial Fibrillation Risk Algorithm in Whites and African Americans

Author Affiliations

Author Affiliations: Department of Medicine 2, Johannes Gutenberg University, Mainz, Germany (Dr Schnabel); National Heart, Lung, and Blood Institute Framingham Study, Framingham, Massachusetts (Drs Schnabel, Pencina, Levy, Kannel, Wolf, Vasan, and Benjamin); Icelandic Heart Association, Heart Preventive Clinic and Research Institute, University of Iceland, Reykjavik (Drs Aspelund and Gudnason); Cardiovascular Health Research Unit, Departments of Medicine (Mr Li and Dr Psaty), Epidemiology (Ms Suchy-Dicey and Drs Psaty and Heckbert), Biostatistics (Dr Kronmal), and Health Services (Dr Psaty), University of Washington, Seattle; Boston University School of Public Health, Departments of Biostatistics (Drs Sullivan, Pencina, and D’Agostino) and Epidemiology (Drs Kannel and Benjamin), and Department of Mathematics and Statistics (Dr D’Agostino), Neurology Department (Dr Wolf), Whitaker Cardiovascular Institute, Evans Memorial Medicine Department, Cardiology Section (Drs Vasan and Benjamin), Preventive Medicine Department (Drs Vasan and Benjamin), School of Medicine, Boston University, Boston, Massachusetts; Laboratory of Epidemiology, Demography, and Biometry, Intramural Research Program, National Institute on Aging, Bethesda, Maryland (Drs Harris and Launer); Center for Population Studies, National Heart, Lung, and Blood Institute, Bethesda (Dr Levy); Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston (Dr Wang); Division of Public Health Sciences, School of Medicine, Wake Forest University, Winston-Salem, North Carolina (Dr Burke); and Group Health Research Institute, Group Health Cooperative, Seattle (Drs Psaty and Heckbert).

Arch Intern Med. 2010;170(21):1909-1917. doi:10.1001/archinternmed.2010.434

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.