Background: Atrial fibrillation (AF) is linked to increased risk of dementia and cognitive decline, but whether AF and its ascertainment methods affect cognition in patients with hypertension has received less attention.
Methods: We studied 8469 participants with elevated systolic blood pressure who were free of stroke and diabetes at baseline enrolled in the Systolic Blood Pressure Intervention Trial. AF was ascertained using three approaches: self-report of AF, AF from a safety event, and study electrocardiogram-determined (ECG) AF. Mild cognitive impairment (MCI) and probable dementia (PD) were ascertained from in-person assessments or telephone interviews from the participant or an informant. We used Cox proportional hazard models to estimate hazard ratios for the association of AF (all three sources) with outcomes of MCI, PD, and a composite MCI/PD outcome.
Results: During a mean follow-up of 4.6 years, 974 (12%) participants had AF (prevalent or incident), 634 were diagnosed with MCI, and 316 with PD. When comparing those with AF (from any source) to those without, no differences were detected in the risk of MCI or PD. Comparison between AF sources found ECG-AF to be associated with an elevated risk of MCI/PD (hazard ratio (HR) 1.59, 95% confidence interval (95%CI) 1.06, 2.38). Neither AF ascertained through safety events nor self-reported AF were associated with MCI or PD.
Conclusion: The association of AF with incidence of MCI/PD differed by method of AF ascertainment. Case definition of AF and quantification of AF burden are important factors in studies evaluating the link between AF and cognitive dysfunction.
Keywords: ascertainment; atrial fibrillation; dementia.