Female sex as a risk factor for stroke in atrial fibrillation: a nationwide cohort study
ABSTRACT 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.
Full-textDOI: · Available from: Christian Torp-Pedersen, Sep 19, 2014
SourceAvailable from: Sophie (Rushton-Mellor) Rushton-SmithJournal of the American College of Cardiology 03/2012; 59(13). DOI:10.1016/S0735-1097(12)60671-8 · 15.34 Impact Factor
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ABSTRACT: Stroke in patients with heart failure is associated with poor outcomes. Risk stratification schemes may improve clinical decision making in this patient population. This study investigated whether female sex is a risk factor for stroke in patients with heart failure in sinus rhythm. This is a population-based cohort study of patients diagnosed with heart failure during 2000 to 2012, identified by record linkage between nationwide Danish registries. Our primary outcome was stroke, and secondary outcome was thromboembolic event. We used relative risks (RRs) after 1 and 5 years to compare males with females within each of the following age groups: 50 to 59 years, 60 to 69 years, 70 to 79 years, 80 to 89 years, and 90+ years. Analyses took into account the competing risks of death. During the study period, 84,142 patients were diagnosed with heart failure, of which 39,946 (47.5%) were females. At 5-year follow-up, female sex was associated with a lower risk of stroke compared with males (adjusted overall hazard ratio 0.91, 95% CI 0.85-0.96). The observed lower risks of stroke in females were not present in the older age groups, where the competing risk of death was substantial among males in particular. When considering a more broadly defined thromboembolic end point, a decreased risk among females persisted across nearly all age groups after 5-year follow-up (adjusted overall hazard ratio 0.93, 95% CI 0.91-0.96). We found an association between female sex and decreased stroke risk in patients with heart failure, which persisted after adjustment for concomitant cardiovascular risk factors. The association was attenuated with increasing age, possibly because of competing risks of death. Copyright © 2014 Elsevier Inc. All rights reserved.American Heart Journal 12/2014; 169(3). DOI:10.1016/j.ahj.2014.12.004 · 4.56 Impact Factor
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ABSTRACT: Background—Among patients with atrial fibrillation (AF), women are at higher risk of stroke than men. Using prospective cohort data from a large global population of patients with nonvalvular AF, we sought to identify any differences in the use of anticoagulants for stroke prevention in women and men. Methods and Results—This was a prospective multicenter observational registry with 858 randomly selected sites in 30 countries. A total of 17 184 patients with newly diagnosed (≤6 weeks) nonvalvular AF and ≥1 additional investigator-defined stroke risk factor(s) were recruited (March 2010 to June 2013). The main outcome measure was the use of anticoagulants (vitamin K antagonists, factor Xa inhibitors, and direct thrombin inhibitors) for stroke prevention at AF diagnosis. Of 17 184 patients enrolled, 43.8% were women. More women than men were at moderate-to-high risk of stroke (CHADS2 score ≥2: 65.1% versus 54.7%). Rates of anticoagulant use were not different overall (60.9% of men versus 60.8% of women) and in patients with a CHADS2 score ≥2 (adjusted odds ratio for women versus men, 1.00; 95% confidence interval, 0.92–1.09). In patients at low risk (CHA2DS2-VASc of 0 in men and 1 in women), 41.8% of men and 41.1% of women received an anticoagulant. In patients at high risk (CHA2DS2-VASc score ≥2), 35.4% of men and 38.4% of women did not receive an anticoagulant. Conclusions—These contemporary global data show that anticoagulant use for stroke prevention is no different in men and women with nonvalvular AF. Thromboprophylaxis was, however, suboptimal in substantial proportions of men and women, with underuse in those at moderate-to-high risk of stroke and overuse in those at low risk.Circulation Cardiovascular Quality and Outcomes 02/2015; DOI:10.1161/CIRCOUTCOMES.114.001556 · 5.66 Impact Factor