Atrial fibrillation was not independently associated with ischemic stroke (HR 1.33; 95% CI 0.88-2.00) or dementia (HR 1.15; 95% CI 0.92-1.43) after adjusting for left atrial reservoir strain.
Cohort (n=5,461)
Yes
Does atrial fibrillation independently increase the risk of ischemic stroke and dementia when accounting for left atrial function and size in older adults?
The association between atrial fibrillation and both ischemic stroke and dementia may be confounded by underlying atrial myopathy (left atrial function and size), suggesting AF may not be an independent risk factor.
Effect estimate: HR 1.33 (95% CI 0.88-2.00)
BACKGROUND: Atrial fibrillation (AF) is associated with higher risks of ischemic stroke (IS) and dementia. Whether alterations in left atrial (LA) function or size-atrial myopathy-confound these associations remains unknown. OBJECTIVES: The purpose of this study was to examine the association of prevalent and incident AF with ischemic stroke and dementia in the ARIC (Atherosclerosis Risk In Communities) study, adjusting for LA function and size. METHODS: Participants at visit 5 (2011-2013) with echocardiographic LA function (reservoir, conduit, contractile strain, and emptying fraction) and size (maximal, minimal volume index) data, and without prevalent stroke or dementia were followed through 2019. For analysis, we used time-varying Cox regression. RESULTS: Among 5,458 participants (1,193 with AF, mean age of 76 years) in the stroke analysis and 5,461 participants (1,205 with AF, mean age of 75 years) in the dementia analysis, 209 participants developed ischemic stroke, and 773 developed dementia over 7.1 years (median). In a demographic and risk factor-adjusted model, AF was significantly associated with ischemic stroke (HR, 1.63; 95% CI: 1.11-2.37) and dementia (HR: 1.38, 95% CI: 1.13-1.70). After additionally adjusting for LA reservoir strain, these associations were attenuated and no longer statistically significant (stroke HR: 1.33, 95% CI: 0.88-2.00, dementia HR: 1.15, 95% CI: 0.92-1.43). Associations with ischemic stroke and dementia were also attenuated and not statistically significant after adjustment for LA contractile strain, emptying fraction, and minimal volume index. CONCLUSIONS: AF-ischemic stroke and AF-dementia associations were not statistically significant after adjusting for measures of atrial myopathy. This proof-of-concept analysis does not support AF as an independent risk factor for ischemic stroke and dementia.
Zhang et al. (Sat,) conducted a cohort in Atrial fibrillation (n=5,461). Atrial fibrillation vs. No atrial fibrillation was evaluated on Ischemic stroke (adjusted for left atrial reservoir strain) (HR 1.33, 95% CI 0.88-2.00). Atrial fibrillation was not independently associated with ischemic stroke (HR 1.33; 95% CI 0.88-2.00) or dementia (HR 1.15; 95% CI 0.92-1.43) after adjusting for left atrial reservoir strain.
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