Sex Difference in the Risk of Dementia in Patients with Atrial Fibrillation.

Yung-Lung Chen,Hui-Ting Wang,Shaur-Zheng Chong,Yu-Sheng Lin,Chang-Ming Chung,Joseph Chen,Ya-Ting Chang,Shukai Hsueh

doi:10.3390/diagnostics11050760

Abstract

Atrial fibrillation (AF) is one of the risk factors for dementia. Female sex is an inconsistent risk factor for dementia after adjusting for age in the general population, and there lacks research on its impact in developing dementia in patients with AF. This paper aims to investigate whether female sex is a risk factor for dementia in AF patients. Data of patients with newly diagnosed AF between 2001–2013 were retrieved from Taiwan’s National Health Insurance Research Database. Exclusion criteria were: patients with incomplete demographic data, age < 20 years, rheumatic heart disease, hyperthyroidism, past valvular heart surgery, and a history of dementia. Propensity score matching (PSM) between sexes was performed, including comorbidities, medications and index date stratified by age. The primary outcome was a new diagnosis of dementia at follow-up. A total of 117,517 men and 156,705 women were eligible for analysis. After 1:1 PSM, both 100,065 men and women (aged 72.5 ± 12.5 years) were included for analysis. Dementia risk varied with age in women compared with men. The difference was negligible for ≤55 years (sub distribution HR (SHR) = 0.89, 95% CI 0.73–1.07), but increased between 56–65 years (SHR = 1.13, 95% CI 1.02–1.25), 66–75 years (SHR = 1.14, 95% CI 1.09–1.20), 75–85 years (SHR = 1.11, 95% CI 1.07–1.15) and >85 years (SHR 1.10, 95% CI 1.04–1.16) for females. This study establishes that female sex increases the risk of developing dementia compared to male sex in AF patients aged >56 years. However, the impact of female sex on dementia in AF patients differs between dementia types.

Highlights

Many epidemiologic studies have suggested that ischemic stroke is a significant risk factor for dementia, and that risk is affected by the size and location of the presenting stroke, intercurrent medical illnesses associated with cerebral hypoxia or ischemia, and older age [11,12,13]
The primary objective of this study is to investigate if female sex is a risk factor for developing dementia in patients with Atrial fibrillation (AF) after adjusting for age and other associated risk factors
Our study evaluated the difference between sexes in the incidence of dementia in patients with a new diagnosis of AF, which showed that the incidence of Alzheimer’s disease (AD), but not vascular dementia, was higher in women than in men, especially in patients older than 55

Summary

Introduction

Previous studies have shown that women have a higher risk of stroke than men in patients with AF [5,6]. The risk of recurrent stroke and mortality is higher in women than in men after the first stroke [8] Some of these disparities in clinical outcomes is possibly related to the older onset of ischemic stroke in women, and age could be a confounding factor in the analysis of these sex differences in ischemic strokes [9,10]. Many epidemiologic studies have suggested that ischemic stroke is a significant risk factor for dementia, and that risk is affected by the size and location of the presenting stroke, intercurrent medical illnesses associated with cerebral hypoxia or ischemia, and older age [11,12,13]. Recent studies suggest that this difference is related to the lifespan of men and women [15,16]

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