Female sex as a risk factor for stroke in atrial fibrillation: A nationwide cohort study

Department of Cardiology, Copenhagen University Hospital Gentofte, Hellerup, Denmark.
Journal of Thrombosis and Haemostasis (Impact Factor: 5.72). 07/2012; 10(9):1745-51. DOI: 10.1111/j.1538-7836.2012.04853.x
Source: PubMed


Female sex has been suggested as a risk factor for stroke/thromboembolism in patients with non-valvular atrial fibrillation (AF) and has therefore been included within risk scores, e.g., the CHA2 DS2 -VASc score, and guidelines.
To investigate the risk of stroke/thromboembolism associated with female sex in non-valvular AF patients.
Using the national Danish registers, we identified non-anticoagulated patients discharged with non-valvular AF (1997-2008), and subdivided the population into three age intervals: < 65, 65-74 and ≥ 75 years. We calculated stroke rates according to sex, and assessed the stroke risk associated with female sex by using Cox regression analysis.
We included 87,202 AF patients, and 44,744 (51.3%) were female. The rate of stroke/thromboembolism for females aged < 65 and 65-74 years was not increased as compared with men, whereas the rate for females aged ≥ 75 years was increased. At both 1-year and 12-year follow-up, female sex did not increase the risk of stroke for patients aged < 75 years. At 1-year follow-up, the hazard ratios associated with female sex were 0.89 (95% confidence interval [CI] 0.70-1.13) and 0.91 (95 CI 0.79-1.05) for patients aged < 65 and 65-74 years, respectively, and being female and aged ≥ 75 years was associated with an increased risk of stroke of 1.20 (95 CI 1.12-1.28).
Female sex was only associated with an increased risk of stroke for AF patients aged ≥ 75 years. Our study suggests that female sex should not be automatically included as an independent stroke/thromboembolic risk factor in guidelines or in the CHA2 DS2 -VASc score, without careful prior consideration of the 'age < 65 and lone AF' criterion.

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    Full-text · Article · Mar 2012 · Journal of the American College of Cardiology
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    ABSTRACT: Decision making with regard to thromboprophylaxis should be based upon the absolute risks of stroke/thromboembolism and bleeding and the net clinical benefit for a given patient. As a consequence, a crucial part of atrial fibrillation (AF) management requires the appropriate use of thromboprophylaxis, and the assessment of stroke as well as bleeding risk can help inform management decisions by clinicians. The objective of this review article is to provide an overview of stroke and bleeding risk assessment in AF. There would be particular emphasis on when, how, and why to use these risk stratification schemes, with a specific focus on the CHADS(2) [congestive heart failure, hypertension, age, diabetes, stroke (doubled)], CHA(2)DS(2)-VASc [congestive heart failure or left ventricular dysfunction, hypertension, age ≥75 (doubled), diabetes, stroke (doubled)-vascular disease, age 65-74 and sex category (female)], and HAS-BLED [hypertension (i.e. uncontrolled blood pressure), abnormal renal/liver function, stroke, bleeding history or predisposition, labile INR (if on warfarin), elderly (e.g. age >65, frail condition), drugs (e.g. aspirin, NSAIDs)/alcohol concomitantly] risk scores.
    No preview · Article · Dec 2012 · European Heart Journal
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    ABSTRACT: BACKGROUND: Female patients with atrial fibrillation (AF) are at increased risk of stroke. It is unclear what contributes to the gender-related differences in stroke and mortality amongst AF patients. This is pertinent since oral anticoagulation use results in a significant reduction in stroke, as well as all-cause mortality. OBJECTIVE: We investigated gender-related risk factors for stroke and mortality in a cohort of Chinese patients with AF. METHODS: We studied 1034 AF patients (27% females, median age 75years) who were followed-up for an average of 1.9years for the principal primary endpoint of 'ischaemic stroke and death'. Gender-specific effect of risk factors for stroke and death was analyzed. RESULTS: Patients at high stroke risk (CHADS(2) or CHADS(2)-VASc≥2) and HAS-BLED≥3 had higher rates of ischaemic stroke and death, but ischaemic stroke rates in females with HAS-BLED≥3 did not differ between CHADS(2) 0-1 and ≥2 (~3 per 100 person-years). On multivariate analysis of non-anticoagulated patients (n=885), independent predictors of 'ischaemic stroke and death' in both males and females were age>75, prior stroke and renal dysfunction (all p<0.05). Independent predictors of 'ischaemic stroke' in females were prior stroke, vascular disease and renal dysfunction (all p<0.05). When females were compared to males, adjusted for baseline characteristics, independent predictors for 'ischaemic stroke and death' amongst females were prior stroke (hazard ratio, HR 2.40; 95% confidence interval, CI, 1.17-4.91, p=0.017) and renal dysfunction (HR 5.30; 95%CI 2.39-11.74, p<0.001). When females were compared to males, renal dysfunction remained a predictor for the secondary endpoints of ischaemic stroke (HR 4.37, p=0.05) and all-cause mortality (HR 4.15, p=0.003). CONCLUSIONS: Renal dysfunction may be a contributor to the greater risk of stroke and death in female Chinese patients with AF. This increased risk is largely driven by the impact on all-cause mortality.
    No preview · Article · Jan 2013 · International journal of cardiology
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