Atrial fibrillation and incident myocardial infarction in the elderly.
BACKGROUND
Atrial fibrillation (AF) has been shown to be independently associated with an increased risk of myocardial infarction (MI) in a predominantly middle-aged population; however, this association has not been examined in older populations.


OBJECTIVE
AF is associated with MI in older adults.


METHODS
A total of 4608 participants (85% white, 40% male) from the Cardiovascular Health Study without evidence of baseline coronary heart disease were included in this analysis. AF cases were identified during the yearly study electrocardiogram, a self-reported history of a physician diagnosis, or by hospitalization data. Incident MI was identified using medical records with local and central adjudication. Cox regression was used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between AF and incident MI.


RESULTS
A total of 434 (9.4%) participants had evidence of AF before incident MI. Over a median follow-up of 12.2 years, a total of 797 (17.3%) participants developed MI. In a multivariable Cox proportional hazards analysis adjusted for socio-demographics, cardiovascular risk factors, and potential confounders, AF was associated with an increased risk of MI (HR: 1.7, 95% CI: 1.4-2.2). A significant interaction was detected by race, with black (HR: 3.1, 95% CI: 1.7-5.6) AF participants having an increased risk of MI compared with whites (HR: 1.6, 95% CI: 1.2-2.1; P interaction = 0.030).


CONCLUSIONS
AF is associated with an increased risk of MI in a population of older adults.
Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina.
Wesley T
WT
O'Neal
Kunal
K
Sangal
Zhu-Ming
ZM
Zhang
Elsayed Z
EZ
Soliman
D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000150:complications*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000150:complications*; D016016:Proportional Hazards Models; D044469:Racial Groups