Incident AF associated with cognitive decline independent of stroke

BOSTON — Incident atrial fibrillation is associated with cognitive decline independent of ischemic stroke, according to new data from the Atherosclerosis Risk in Communities Neurocognitive Study.

Previous research demonstrated a relationship between AF and cognitive decline, but those studies were mostly hospital-based, had limited follow-up and included mostly white patients.

Researchers evaluated the association of incident AF with cognitive decline in 20-year follow-up of participants from Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS), a biracial community-based prospective cohort study. The findings were presented at the Heart Rhythm Society Annual Scientific Sessions.

Lin Yee Chen

Lin Yee Chen, MD, MS, FHRS, medical director of the cardiac electrophysiology laboratory at the University of Minnesota Medical Center, Minneapolis, and colleagues analyzed 10,429 ARIC-NCS participants (mean age at baseline, 56.7 years; 56% women; 22% black). Each participant had a cognitive test performed in 1990-1992 and at least one more in 1996-1998 or 2011-2013.

Incident AF was ascertained from hospital discharge codes and study ECGs. Ischemic strokes were adjudicated by a committee of physicians. The researchers assessed the association between time-dependent AF and change in z scores of cognitive tests.

During a median 19.4 years of follow-up, Chen and colleagues identified 610 cases of incident AF. After multivariable adjustment, incident AF was associated with greater decline in global cognitive function (additional cognitive change in z score, –0.102; 95% CI, –0.201 to –0.002) and digit symbol substitution, a test of processing speed (additional cognitive change in z score, –0.091; 95% CI, –0.167 to –0.016), even after accounting for interim ischemic stroke.

After multivariable adjustment, the researchers did not find any significant differences between patients who had AF and those who did not in regards to decline in delayed word recall (additional cognitive change in z score, –0.083; 95% CI, –0.232 to 0.065); or word fluency (additional cognitive change in z score, –0.09; 95% CI, –0.185 to 0.005). Analysis using multiple imputation by chained equations to account for differential loss to follow-up bias did not significantly alter the results.

“Our findings confirm that AF-related cognitive decline is independent of ischemic stroke and support further efforts to elucidate its mechanism,” Chen and colleagues wrote in an abstract. – by Erik Swain

Reference:

Chen LY, et al. Abstract AB13-03. Presented at: Heart Rhythm Society Annual Scientific Sessions; May 13-16, 2015; Boston.

Disclosure: Chen reports no relevant financial disclosures.