CV Risk Factors May Precede Atrial Fibrillation Diagnosis By Several Years

Prevalence of stroke, myocardial infarction (MI), and heart failure increased sharply during the time of atrial fibrillation (AF) diagnosis, according to an analysis of the ARIC study (Atherosclerosis Risk in Communities), published in Circulation.

Faye L. Norby, MS, MPH, of the School of Public Health at the University of Minnesota in Minneapolis and colleagues assessed development of cardiovascular risk factors in relation to AF in 2456 patients with incident AF and 6414 matched control individuals, and determined the cardiovascular risk factor trajectories with the incidence of AF among 10,559 individuals without AF.

“Although it is known that AF is a risk factor for stroke and therefore most often precedes it, AF and HF [heart failure] show a bidirectional relation, and the existing severity of specific cardiovascular risk factors, along with age and sex, may determine whether AF or HF occurs first,” researchers wrote. “However, no information exists on the timing relative to the AF diagnosis of the development of other AF risk factors such as hypertension and obesity.”

Ms Norby and colleagues identified 2 goals of their study: “to describe the long-term prevalence of risk factors preceding AF diagnosis and subsequent development of cardiovascular outcomes after diagnosis and compare the risk factors and outcomes by AF status, and to identify subgroups with similar trajectories of risk factors and outcomes and determine the association of these trajectory subgroups with the subsequent development of AF.”

They discovered that patients with AF had higher BMIs, as well as greater prevalence of smoking, hypertension, heart failure, MI, and stroke. There was a J-shaped pattern to the prevalence of heart failure, MI, and stroke in these patients, with a low prevalence in the 10+ years before AF developed and sharp increases in prevalence just before AF diagnosis. In the control group, the prevalence of heart failure, MI, and stroke remained low throughout follow-up for both blacks and whites.

In addition, researchers found that the odds of having heart failure approximately 10 years prior to AF diagnosis is about 50% lower compared with having heart failure at the time of AF diagnosis. However, the odds of having diabetes or hypertension is only approximately 20% lower 10 years before AF diagnosis. Odds ratios over time were significantly different on the basis of AF status for hypertension, obesity, heart failure, stroke, and MI (P<.05 for all interaction terms), with lower increments in those without AF.

The 10,559 individuals who were AF-free at the start of the study were fitted to each of the cardiovascular risk factors and outcomes. Researchers indentified distinct trajectories for BMI, obesity, and systolic blood pressure; 4 distinct trajectories were also identified for hypertension, smoking, diabetes, heart failure, MI, and stroke.

During a 15-year follow-up of these groups, incident AF was detected in 1507 patients. Incident AF risk was highest in those in the trajectory group with the highest prevalence of risk factor values and lowest in the reference trajectory group. For example, there was a 39% increased risk of AF in the long-term obese group compared with the nonobese group (ie, the reference trajectory group), even after BMI adjustment at the final visit.

“This large community-based study with 25 years of follow-up demonstrated an increased prevalence of cardiovascular risk factors in AF patients many years before disease diagnosis and identified diverse trajectories in the prevalence of these risk factors, highlighting their different roles in AF pathogenesis and the need to establish preventive strategies that address risk factors decades before AF diagnosis,” the authors concluded.

Reference

Norby FL, Soliman EZ, Chen LY, et al. Trajectories of cardiovascular risk factors and incidence of atrial fibrillation over a 25-year follow-up. The ARIC Study (Atherosclerosis Risk in Communities). Circulation. 2016;134:599-610. doi:10.1161/CIRCULATIONAHA.115.020090.