Development of a risk score for atrial fibrillation (Framingham Heart Study): a community-based cohort study.
BACKGROUND
Atrial fibrillation contributes to substantial increases in morbidity and mortality. We aimed to develop a risk score to predict individuals' absolute risk of developing the condition, and to provide a framework for researchers to assess new risk markers.


METHODS
We assessed 4764 participants in the Framingham Heart Study from 8044 examinations (55% women, 45-95 years of age) undertaken between June, 1968, and September, 1987. Thereafter, participants were monitored for the first event of atrial fibrillation for a maximum of 10 years. Multivariable Cox regression identified clinical risk factors associated with development of atrial fibrillation in 10 years. Secondary analyses incorporated routine echocardiographic measurements (5152 participants, 7156 examinations) to reclassify the risk of atrial fibrillation and to assess whether these measurements improved risk prediction.


RESULTS
457 (10%) of the 4764 participants developed atrial fibrillation. Age, sex, body-mass index, systolic blood pressure, treatment for hypertension, PR interval, clinically significant cardiac murmur, and heart failure were associated with atrial fibrillation and incorporated in a risk score (p<0.05, except body-mass index p=0.08), clinical model C statistic 0.78 (95% CI 0.76-0.80). Risk of atrial fibrillation in 10 years varied with age: more than 15% risk was recorded in 53 (1%) participants younger than 65 years, compared with 783 (27%) older than 65 years. Additional incorporation of echocardiographic measurements to enhance the risk prediction model only slightly improved the C statistic from 0.78 (95% CI 0.75-0.80) to 0.79 (0.77-0.82), p=0.005. Echocardiographic measurements did not improve risk reclassification (p=0.18).


CONCLUSIONS
From clinical factors readily accessible in primary care, our risk score could help to identify risk of atrial fibrillation for individuals in the community, assess technologies or markers for improvement of risk prediction, and target high-risk individuals for preventive measures.
Schnabel
Renate B
RB
Framingham Heart Study, Framingham, MA, USA; Department of Medicine II, Johannes Gutenberg-University, Mainz, Germany.
Sullivan
Lisa M
LM
Levy
Daniel
D
Pencina
Michael J
MJ
Massaro
Joseph M
JM
D'Agostino
Ralph B
RB
Newton-Cheh
Christopher
C
Yamamoto
Jennifer F
JF
Magnani
Jared W
JW
Tadros
Thomas M
TM
Kannel
William B
WB
Wang
Thomas J
TJ
Ellinor
Patrick T
PT
Wolf
Philip A
PA
Vasan
Ramachandran S
RS
Benjamin
Emelia J
EJ
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000209:etiology* / Q000517:prevention & control; D003256:Community Participation; D005260:Female; D006337:Heart Murmurs / Q000150:complications*; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000188:drug therapy; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012307:Risk Factors; D012737:Sex Factors; D014463:Ultrasonography