Anticoagulation in women with non-valvular atrial fibrillation in the stroke prevention using an oral thrombin inhibitor (SPORTIF) trials

Association of Sex With Stroke and Bleeding Risk of Apixaban and Rivaroxaban in Elderly Atrial Fibrillation Patients Using Propensity Score Weights

Background

Evidence from clinical trials suggests a differential effect of sex on the effectiveness and safety of direct oral anticoagulants (DOACs) for stroke prophylaxis in atrial fibrillation (AF).

Methods

This population-based cohort study examined the independent effect of sex on hemorrhage and ischemic stroke in 23,884 patients (55% females; age ≥ 66 years) with AF starting apixaban or rivaroxaban treatment in Ontario, Canada. Patients were followed for 90 days after their DOAC prescription. Using female sex as the exposure of interest, differences in baseline characteristics were balanced between sexes using inverse probability weights based on propensity scores. Applying weighted modified Poisson regression, risk ratios (RRs) were estimated for major hemorrhage, ischemic stroke/systemic embolism/transient ischemic attack (hereafter stroke), myocardial infarction, and all-cause mortality, with males as a reference.

Results

Females were older, had higher predicted stroke risk (based on CHADS₂ score), and had fewer comorbidities than did males. Males had a higher prevalence of coronary artery disease, diabetes, and cancer, and similar predicted bleeding risk (based on HAS-BLED score). After weighting, baseline characteristics were well balanced. The 90-day risks for hemorrhage (RR 0.96; 95% confidence interval [CI] 0.80-1.15; P = 0.69) and stroke (RR 1.01; 95% CI 0.86-1.19; P = 0.94) were similar between sexes, which remained true when assessing each DOAC separately by dosing regimen. Compared to males, females had a lower risk for myocardial infarction (RR 0.66; 95% CI 0.52-0.84; P = 0.0008), and for all-cause mortality (RR 0.76; 95% CI 0.67-0.87; P < 0.0001).

Conclusions

Our findings do not suggest an association of sex with the 90-day risk of hemorrhage or ischemic stroke in older AF patients prescribed apixaban or rivaroxaban.

Gender Differences in the Impact of New-Onset Atrial Fibrillation on Long-Term Risk of Ischemic Stroke after Acute Myocardial Infarction

BACKGROUND

Atrial fibrillation (AF) has been identified as a major risk factor for mortality after acute coronary syndrome (ACS). However, the long-term risk of ischemic stroke associated with new-onset atrial fibrillation (NOAF) in ACS remains controversial, and its gender-specific association is unknown.

METHODS

We analyzed the data of 10,137 ACS survivors included in a multicenter, prospective registry for Korean patients with acute myocardial infarction (AMI) between January 2004 and August 2014. Subjects were categorized into three groups (non-AF vs. NOAF vs. previous AF) based on medical history and electrocardiographic evidence of AF, either at admission or during hospitalization.

RESULTS

Among the total study population (72.3% men), 370 patients (3.6%) had NOAF and 130 (1.3%) had previous AF. During a median follow-up of 61 months (interquartile range, 38.8 to 89.3 months), 245 (2.4%) patients (218 (2.3%) non-AF vs. 15 (4.1%) NOAF vs. 12 (9.2%) previous AF, p < 0.001) experienced ischemic stroke. After adjustment for confounding variables, both NOAF (adjusted hazard ratio (HR) 1.87, 95% confidence interval (CI) 1.09-3.24, p = 0.024) and previous AF (adjusted HR 4.00, 95% CI 2.03-7.87, p < 0.001), along with older age, diabetes, current smoker, and previous stroke were independent risk factors of ischemic stroke. In the gender-stratified analysis, men with previous AF but not NOAF had a significantly higher risk of ischemic stroke (adjusted HR 4.14, 95% CI 1.79-9.55, p = 0.001) than those without AF. In women, NOAF (adjusted HR 2.54, 95% CI 1.21-5.35, p = 0.014) as well as previous AF (adjusted HR 3.72, 95% CI 1.16-11.96, p = 0.028) was a strong predictor of ischemic stroke, and the predictive value was comparable to that of previous AF among patients with a CHA₂DS₂-VASc score ≥ 2.

CONCLUSIONS

Both NOAF and previous AF were associated with ischemic stroke after AMI, but the impact of NOAF as a risk factor of ischemic stroke was significant only in women.

Low Quality of Warfarin Therapy is Associated With Female Gender but Not With Polypharmacy in Patients With Atrial Fibrillation

Background: We examined the impact of polypharmacy on the quality of the anticoagulation therapy in patients with atrial fibrillation. We also examined the factors that affect the stability of warfarin therapy.

Methods and Results: This retrospective study was conducted using data from 157 consecutive outpatients with atrial fibrillation in a single tertiary referral hospital. Patients who were prescribed warfarin continuously and for whom PT-INR was examined at least three times in a year were included in this study. We examined the quality of warfarin therapy using time in the therapeutic INR range (TTR), percentage of PT-INR determinations in range (PINRR), and the coefficient variation (CV) of PT-INR. We found that the number of prescribed medicines was significantly associated with high BMI and low eGFR, but not with TTR, PINRR, and the coefficient variation of PT-INR in patients with atrial fibrillation. We also found that female gender was independently associated with low PINRR in this study population.

Conclusion: Polypharmacy did not deteriorate the quality of warfarin therapy in patients with atrial fibrillation treated in the tertiary referral hospital. Female gender was an independent predictor of the low quality of warfarin therapy.

Comparison of the Efficacy and Safety Outcomes of Edoxaban in 8040 Women Versus 13 065 Men With Atrial Fibrillation in the ENGAGE AF-TIMI 48 Trial

Supplemental Digital Content is available in the text.

Background:

Female sex is an independent risk factor for stroke and systemic embolic events in patients with atrial fibrillation. This study aimed to examine the efficacy and safety profile of edoxaban in women versus men.

Methods:

The ENGAGE AF-TIMI 48 trial (Effective Anticoagulation with Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis in Myocardial Infarction 48) randomly assigned 21 105 patients (8040 women) with atrial fibrillation and CHADS₂ score ≥2 either to a higher-dose edoxaban regimen, a lower-dose edoxaban regimen, or warfarin. The primary end points of the trial were the composite of stroke or systemic embolic events (efficacy), and International Society on Thrombosis and Haemostasis–defined major bleeding (safety).

Results:

In comparison with men, women were older, had lower body weight, were more likely to have hypertension and renal dysfunction, but less likely to smoke, drink alcohol, or have diabetes or coronary artery disease. Pretreatment endogenous factor Xa activity was significantly higher in women than in men (92.5% versus 86.1%, P<0.001). Treatment with edoxaban in women resulted in greater peak edoxaban concentration and inhibition of endogenous factor Xa in comparison with men, resulting in similar endogenous factor Xa activity between the sexes 2 to 4 hours after dose. Treatment with higher-dose edoxaban regimen (versus warfarin) resulted in similar reduction in the risk of stroke/systemic embolic events (women: hazard ratio [HR], 0.87 [0.69–1.11], men: HR, 0.87 [0.71–1.06]; P-interaction=0.97) and major bleeding (women: HR, 0.74 [0.59–0.92], men: HR, 0.84 [0.72–0.99]; P-interaction=0.34) in women and men. However, women assigned to higher-dose edoxaban regimen experienced greater reductions in hemorrhagic stroke (HR, 0.30 [95% CI, 0.15–0.59] versus HR, 0.70 [95% CI, 0.46–1.06]), intracranial bleeding (HR, 0.20 [95% CI, 0.10–0.39] versus HR, 0.63 [95% CI, 0.44–0.89]), and life-threatening or fatal bleeding (HR, 0.25 [95% CI, 0.15–0.42] versus HR, 0.72 [95% CI, 0.54–0.96]) than men (each P-interaction<0.05).

Conclusions:

Despite many differences in baseline characteristics between women and men and higher baseline endogenous factor Xa levels in women, the intensity of anticoagulation achieved with edoxaban between the sexes was similar. Treatment with higher-dose edoxaban regimen resulted in an even greater reduction in hemorrhagic stroke and several serious bleeding outcomes in women than in men, whereas the efficacy profile was similar between sexes.

Risk factors for severe bleeding events during warfarin treatment: the influence of sex, age, comorbidity and co-medication

PURPOSE

To investigate risk factors for severe bleeding during warfarin treatment, including the influence of sex, age, comorbidity and co-medication on bleeding risk.

METHODS

Patients initiating warfarin treatment between 2007 and 2011 were identified in the nationwide Swedish Prescribed Drug Register, and diagnoses of severe bleeding were retrieved from the National Patient Register. Hazard ratios (HR) with 95% confidence intervals (CI) for severe bleeding were estimated using multiple Cox regression adjusting for indications and including covariates age, sex, comorbidities and co-medications. Interactions between sex and other covariates were investigated.

RESULTS

The study cohort included 232,624 patients ≥ 18 years (101,011 women and 131,613 men). The incidence rate of severe bleeding was 37 per 1000 person-years, lower among women than men with an adjusted HR (95% CI) of 0.84 (0.80-0.88). Incidence of bleeding increased with age, HR 2.88 (2.37-3.50) comparing age ≥ 80 to < 40 years, and comorbidities associated with the highest risk of severe bleeding were prior bleeding, HR 1.85 (1.74-1.97); renal failure, HR 1.82 (1.66-2.00); and alcohol dependency diagnosis, HR 1.79 (1.57-2.05). Other comorbidities significantly associated with bleeding events were hypertension, diabetes, peripheral vascular disease, congestive heart failure, liver failure, stroke/TIA, COPD and cancer.

CONCLUSION

Most of the well-established risk factors were found to be significantly associated with bleeding events in our study. We additionally found that women had a lower incidence of bleeding. Potential biases are selection effects, residual confounding and unmeasured frailty.

Differences in the risk of stroke, bleeding events, and mortality between female and male patients with atrial fibrillation during warfarin therapy

Aims

Females with atrial fibrillation (AF) have been suggested to carry a higher risk for thromboembolic events than males. We compared the residual risk of stroke, bleeding events, and cardiovascular and all-cause mortality among female and male AF patients taking warfarin.

Methods and results

Data from several nationwide registries and laboratory databases were linked with the civil registration number of the patients. A total of 54 568 patients with data on the quality of warfarin treatment (time in therapeutic range) 60 days prior to the events were included (TTR60). Gender differences in the endpoints were reported for the whole population, pre-specified age groups, and different TTR60 groups. During the 3.2 ± 1.6 years follow-up, there were no differences in the adjusted risk of stroke [hazard ratio (HR) 0.97, 95% confidence interval (CI) 0.91-1.03, P = 0.304] between the genders. Cardiovascular mortality (HR 0.82, 95% CI 0.78-0.88, P < 0.001) and all-cause mortality (HR 0.79, 95% CI 0.75-0.83, P < 0.001) were lower in women when compared with men. There were no differences in the risk of stroke, cardiovascular mortality, and all-cause mortality between the genders in the TTR60 categories except for those with TTR60 <50%. Bleeding events were less frequent in females (HR 0.52, 95% CI 0.49-0.56, P < 0.001).

Conclusion

There were no differences in the risk of stroke between female and male AF patients taking warfarin. Cardiovascular mortality, all-cause mortality, and risk of bleeding events were lower in females. Hence, female gender was not a risk marker for adverse outcomes in AF patients with proper warfarin therapy.

The safety of NOACs in atrial fibrillation patient subgroups: A narrative review

AIM

Four non-vitamin K oral anticoagulants (NOACs) have been evaluated in clinical trials for the prevention of stroke in patients with atrial fibrillation (AF). Although each of the NOACs have been shown to be at least non-inferior to warfarin for efficacy and safety outcomes, controversy remains over the relative safety of each NOAC inpatient subgroups. This narrative review provides an overview of phase III data on NOAC trials for the prevention of stroke in AF, with a focus on reporting the safety of each agent in key patient subgroups based on age, gender, accumulated risk factors, and primary or secondary prevention of stroke.

METHODS

A comprehensive literature search was completed and, where data permit, analyses of phase III trials of the NOACs are presented for each patient subgroup.

RESULTS

Analyses of key safety outcomes from NOAC trials were completed using primary trial data, including major bleeding and all-cause mortality. The safety of NOACs was generally consistent and favourable compared with warfarin according to patient age, gender, previous history of stroke, and the presence of risk factors for stroke.

CONCLUSIONS

The safety of the NOACs compared with warfarin was generally favourable across different patient subgroups, including those perceived to be at "high risk" for adverse outcomes. However, certain NOACs may be preferable to warfarin in some subgroups, based on indirect analyses.

Sex differences in stroke and major adverse clinical events in patients with atrial fibrillation: A systematic review and meta-analysis of 993,600 patients

BACKGROUND

Atrial fibrillation (AF) is the most commonly diagnosed arrhythmia, which is associated with an increased risk of stroke. Several studies have suggested that female AF patients could have a greater risk for stroke and thromboembolic events (TE).

METHODS

A systematic literature review update and meta-analysis was conducted using Pubmed. The search used the terms "atrial fibrillation", "gender", "sex", "female", "women", "stroke", "thromboembolism". Main aim of the study was to compare and male AF patients for occurrence of stroke and TE. Secondary outcomes were: major bleeding, cardiovascular (CV) death and all-cause death.

RESULTS

Forty-four studies were included in the analysis including 993,603 patients (48.9% women). After pooling the data, there was a higher risk of stroke for women vs. male AF patients (hazard ratio [HR]: 1.24; 95% confidence intervals [CIs]: 1.14-1.36). Overall, TE risk was not different between female and male patients, despite sensitivity analysis left some uncertainties. No sex differences were found for major bleeding, CV death and all-cause death. A significant relationship between increasing age and the difference in stroke risk between female and male AF patients was found (Delta HR: 1.01; 95% CI: 1.00-1.03 for each year of age increase).

CONCLUSIONS

Female patients with AF are at increased risk of stroke compared to men. A significant relationship between increasing age and stroke risk in women compared to men was found, most evident at age > 65 years. Female sex may act as a stroke risk modifier, particularly in elderly and very elderly AF subjects, conferring a significant increase in stroke risk.

Revisiting sex differences in outcomes in non-valvular atrial fibrillation: a population-based cohort study

Aims

In patients with non-valvular atrial fibrillation (NVAF), it is uncertain whether the higher risk of ischaemic stroke in women reported in some studies is due to residual confounding. We assessed this association using standard time-fixed and more accurate time-dependent adjustment for confounders.

Methods and results

Using the computerized databases of the Régie de l'assurance maladie du Québec (RAMQ), we identified a cohort of patients with NVAF during 2000-2009 and RAMQ medication coverage. Cox proportional hazards models were used to estimate the hazard ratio (HR) of ischaemic stroke, death, and bleeding, associated with sex, adjusting for time-fixed covariates at cohort entry. This was compared with adjustment for time-dependent covariates using an age and time-matched nested case-control analysis. The cohort included 147 622 patients. During a mean follow-up of 2.9 years 11 326 patients had a stroke (incidence rate 2.6 per 100 per year). Using time-fixed adjustment for confounders, women had a moderately higher risk of ischaemic stroke than men (HR 1.16 (Confidence interval (CI) 95% 1.11-1.21). Matching on age and using time-dependent adjustment for confounders, women were not at higher risk of stroke than men (Rate Ratio 1.01; 95% CI 0.97-1.05). Mortality and bleeding rates were lower in women compared with men in both analyses.

Conclusion

In NVAF, women were not at higher risk of thromboembolic events than men in our study. The small increased risk reported in previous studies may be related to residual confounding, in particular from insufficient control for age.

Gender and AF: Differences and Disparities

AF is the most common clinical arrhythmia encountered. A wealth of evidence has improved our ability to diagnose and effectively treat AF. An intriguing aspect of this common disease – gender-based differences – is well recognized, but poorly understood. In this brief review, we will explore the accumulating evidence suggesting a gender-based disparity in the prevalence, pathogenesis and management of AF.

Influence of renal function on anticoagulation control in patients with non-valvular atrial fibrillation taking vitamin K antagonists

BACKGROUND AND PURPOSE

Chronic kidney disease (CKD) has been related to poor anticoagulation control and an increased risk of bleeding. This study aims to evaluate the association between impaired renal function (eGFR <60 mL/min/1.73 m² ) and anticoagulation control in patients with non-valvular atrial fibrillation (AF) on vitamin K antagonists (VKA) therapy. We also assessed whether the predictive value of the SAMe-TT₂ R₂ score prevailed for subgroups both with and without CKD.

METHODS

This is an ancillary analysis of 1381 patients from the PAULA study, which was a cross-sectional, retrospective and nationwide multicenter study.

RESULTS

A total of 370 patients had eGFR <60 mL/min/1.73 m² . Anticoagulation control levels progressively worsened across each stage of CKD. Multiple linear regression analysis showed CKD as an independent predictor of time in therapeutic range (TTR). In the subgroup of patients with preserved renal function, female sex, diet affecting INR, polypharmacy and amiodarone were associated with poorer TTR. The SAMe-TT₂ R₂ score had a significant but modest predictive value for TTR<65% (AUC, area under the curve 0.558, P = .002). In the subgroup of patients with CKD, the SAMe-TT₂ R₂ (>2 points) showed no significant predictive capacity for TTR (AUC 0.528, P = .354). The average TTR was similar for both sexes (P = .255), but with a higher percentage of males subjects with TTR ≥65% (P = .013).

CONCLUSION

Chronic kidney disease is associated with poor anticoagulation control in patients with non-valvular AF taking VKA. The SAMe-TT₂ R₂ score was not predictive of poor TTR in the subgroup with CKD, although a modest predictive value for poor TTR was found in those without CKD.

Sex-Related Differences in the Clinical Events of Patients With Atrial Fibrillation - The Fushimi AF Registry

BACKGROUND

Female sex is considered a risk factor for thromboembolism in patients with atrial fibrillation (AF), and is included in the risk stratification scheme, CHA₂DS₂-VASc score. The purpose of the present study was to investigate the clinical outcomes of female Japanese AF patients.Methods and Results:The Fushimi AF Registry is a community-based prospective survey of the AF patients in Fushimi-ku, Kyoto. Follow-up data were available for 3,878 patients. Female AF patients (n=1,551, 40.0%) were older (77.0 vs. 71.4 years; P<0.001) than male patients (n=2,327, 60.0%). Female patients were more likely to have heart failure (31.1% vs. 23.7%; P<0.001). Previous stroke incidence (19.2% vs. 21.4%; P=0.083) was comparable between male and female patients. During the median follow-up period of 1,102 days, Cox regression analysis demonstrated that female sex was not independently associated with a risk of stroke or systemic embolism (adjusted hazard ratio [HR] 0.74; 95% confidence interval [CI]: 0.54-1.00, P=0.051). However, female sex showed an association with a lower risk of intracranial hemorrhage (adjusted HR 0.54; 95% CI: 0.30-0.95, P=0.032) and all-cause death (adjusted HR 0.56; 95% CI: 0.46-0.68, P<0.001).

CONCLUSIONS

We demonstrated that female sex is not independently associated with an increased risk of thromboembolism, but is associated with a decreased risk of intracranial hemorrhage and all-cause death in Japanese AF patients enrolled in the Fushimi AF Registry.

From head to toe: Sex and gender differences in the treatment of ischemic cerebral disease

Stroke is a major cause of mortality and morbidity, particularly in the older ages. Women have a longer life expectancy and are more likely to experience stroke than men. Interestingly, the increased risk of ischemic stroke in women seems to be independent from age or classical cardiovascular risk factors. Notwithstanding the fact that stroke outcomes and survival are usually poorer in women, current evidence suggests that thrombolysis, antiplatelet and anticoagulant therapies are more beneficial in women than in men. A possible explanation of this paradox might be that females are often undertreated and they have fewer chances to be submitted to an effective and timely treatment for stroke than the male counterpart. The first step in the attempt to solve this obvious discrimination is surely to emphasize any reasons for differences in the therapeutic approach in relation to gender and then to denounce the lack of a sustainable motivation for them. In this article, we aimed to review the existing literature about gender-related differences on efficacy, administration and side effects of the most common drugs used for the treatment of ischemic stroke. The most striking result was the evidence that the therapeutic approach for stroke is often different according to patients' gender with a clear detrimental prognostic effect for women. A major effort is necessary to overcome this problem in order to ensure equal right to treatment without any sexual discrimination.

Sex Differences in Outcomes among Stroke Survivors with Non-Valvular Atrial Fibrillation in China

Atrial fibrillation (AF) significantly increases the risk of stroke and disease burden and is an established predictor of poor outcomes after stroke. However, data regarding sex differences in long-term outcomes following stroke in patients with AF are scarce. We thus aimed to assess these differences. We recruited 951 consecutive patients with acute ischemic stroke and non-valvular atrial fibrillation (NVAF) treated at three hospitals in Tianjin, China, from January 2006 to September 2014. Information regarding stroke subtype, severity, risk factors, and outcomes (mortality, dependency, and recurrence) at 3, 12, and 36 months after stroke was recorded. The prevalence of NVAF was 8.4% overall, with a higher frequency in women than in men (11.3 vs. 6.9%, P < 0.001). Among patients with NVAF, women were older than men. Women were more likely than men to have severe stroke (38.8 vs. 29.5%, P < 0.001), high levels of total cholesterol and high- and low-density lipoprotein cholesterol (all P < 0.001), hypertension (69.1 vs. 61.2%, P = 0.012), dyslipidemia (29.8 vs. 20.7%, P = 0.001), and obesity (18.5 vs. 11.6%, P = 0.003); they were less likely than men to be current smokers (12.2 vs. 33.6%, P < 0.001) and to consume alcohol (0.9 vs. 13.9%, P < 0.001). There were greater risks of dependency and recurrence at 36 months after stroke in women than in men [odds ratios (95% confidence intervals), 1.64 (1.02–2.64) for dependency, P = 0.043; and 2.03 (1.28–3.20) for recurrence, P = 0.002] after adjustment for stroke subtype, severity, and risk factors. These findings suggest that it is crucial to emphasize the need for individualized stroke prevention education and promotion of healthy lifestyles in order to improve NVAF-related stroke outcomes and reduce disease burden in women.

Impact of gender on event rates at 1 year in patients with newly diagnosed non-valvular atrial fibrillation: contemporary perspective from the GARFIELD-AF registry

OBJECTIVES

Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) explored the impact of gender, risk factors and anticoagulant (AC) treatment on 1-year outcomes in patients with non-valvular atrial fibrillation (NVAF).

DESIGN

GARFIELD-AF is a prospective non-interventional registry.

SETTING

Investigator sites (n=1048) are representative of the care settings/locations in each of the 35 countries.

PARTICIPANTS

Patients ≥18yrs with newly diagnosed (≤6 weeks' duration) NVAF and ≥1 investigator-determined stroke risk factors.

MAIN OUTCOME MEASURES

Event rates per 100 person-years were estimated from the Poisson model and HRs and 95% CIs calculated.

RESULTS

Of 28 624 patients (women 44.4%; men 55.6%) enrolled, there were more elderly (≥75 years) women (46.9%) than men (30.4%). All-cause mortality rates per 100 person-years (95% CI) for women and men were 4.48 (4.12 to 4.87) and 4.04 (3.74 to 4.38), respectively, stroke/systemic embolism (SE) (1.62 (1.41 to 1.87) and 1.17 (1.01 to 1.36)) and major bleeding (0.93 (0.78 to 1.13) and 0.79 (0.66 to 0.95)). After adjustment for baseline risk factors in treated and untreated patients, HRs (95% CI) for women (relative to men) for stroke/SE rates were 1.3-fold higher in women (HR 1.30 (1.04 to 1.63)), and similar for major bleeding (1.13 (0.85 to 1.50)) and all-cause mortality (1.05 (0.92 to 1.19)). Antithrombotic treatment patterns in men and women were almost identical. 63.8% women and 62.9% men received AC± antiplatelets. Relative to no AC treatment, the reduction in stroke/SE rates with AC treatment was greater (p=0.01) in men (HR 0.45 (0.33 to 0.61)) than women 0.77 (0.57 to 1.03). All-cause mortality reduction with AC treatment was similar (women: 0.65 (0.54 to 0.77); men: 0.57 (0.48 to 0.68)). The risk of major bleeding when treated with AC versus no AC was 2.33 (1.41 to 3.84) in men and 1.86 (1.16 to 2.99) in women (p value=0.53).

CONCLUSIONS

Women have a higher risk of stroke/SE and the reduction in stroke/SE events rates with AC treatment is less in women than in men.

TRIAL REGISTRATION NUMBER

NCT01090362.

Primary and key secondary results from the ROCKET AF trial, and their implications on clinical practice

BACKGROUND

The safety and efficacy of the oral anticoagulant rivaroxaban were studied in the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF trial). A number of subanalyses of the ROCKET AF trial have subsequently analyzed the use of rivaroxaban in special patient populations.

METHODS

The outcomes of the ROCKET AF trial were reviewed. The use of rivaroxaban in higher risk populations, as determined by the presence of co-morbidities included in the CHADS2 criteria, was analyzed. Requirements for dose adjustment in patients with renal impairment and in East Asian patients were described. Finally, clinical management challenges, including interruptions in therapy, drug discontinuation, management of bleeding events, drug interactions, and management of patients requiring cardioversion/ablation were reviewed.

RESULTS

Rivaroxaban is efficacious in high-risk populations, including elderly patients, patients with diabetes, heart failure, history of stroke, prior myocardial infarction, or peripheral arterial disease (PAD). Patients with PAD have a higher risk of bleeding with rivaroxaban compared with warfarin. East Asian populations do not require a dose adjustment for rivaroxaban, while a reduced dose of 15 mg daily is required for patients with moderate renal impairment. Rivaroxaban remains effective with temporary interruptions in therapy and in patients requiring cardioversion/ablation. Rates of major bleeding and subsequent outcomes were similar in patients on warfarin and rivaroxaban, although rates of gastrointestinal bleeding were higher with rivaroxaban. Concurrent use of antiarrhythmic therapy was not associated with adverse outcomes.

CONCLUSIONS

Rivaroxaban represents an efficacious alternative to warfarin in high-risk patients with AF. Dose adjustment is required for patients with moderate renal impairment. Rivaroxaban can be used safely in a number of challenging clinical management scenarios although the concurrent use of amiodarone requires more study.

Safety of warfarin in "high-risk" populations: A meta-analysis of randomized and controlled trials

INTRODUCTION

Few data are available about safety of vitamin K antagonists (VKAs) in patients with clinical/demographic characteristics predisposing to an increased risk of bleeding. We performed a meta-analysis to evaluate the safety of VKAs in patients with atrial fibrillation (AF) or venous thromboembolism (VTE) in the following subgroups of "high-risk" patients: elderly patients, patients with low body weight and patients with impaired renal function.

MATERIALS AND METHODS

Major electronic databases were systematically searched to identify randomized controlled trials (RCTs) addressing this issue. Pooled Risk Ratios (RR) and 95% Confidence Intervals (CI) were calculated for each outcome using a random effects model.

RESULTS

Eleven RCTs for a total of 41,015 patients treated with VKAs (25,901 with AF and 15,114 with VTE) were included. We found a significant association between age>75years and bleeding in patients receiving VKAs (RR: 1.62, 95%CI: 1.28-2.05; P<0.0001). Moreover, the prevalence of bleeding events under VKAs was significantly higher in patients with low body weight (RR: 1.20, 95%CI: 1.03-1.40; P=0.02) and in those with impaired renal function (RR: 1.59, 95%CI: 1.30-1.94; P<0.00001). Results were confirmed when separately analyzing data on AF and VTE. Regression models showed that treatment duration did not impact on the differences found in the safety profile of VKAs in different settings analyzed.

CONCLUSIONS

Results of our meta-analysis suggest an increased risk of bleeding complications in "high-risk" patients. Although all results are significant, other studies focused on this issue are warranted to further validate these results.

Atrial fibrillation in women: treatment

Sex-specific differences in the epidemiology, pathophysiology, presentation, prognosis, and treatment of atrial fibrillation (AF) are increasingly recognized. Women with AF generally experience worse symptoms, poorer quality of life, and have higher risk of stroke and death than men with AF. Effective treatment of the arrhythmia in women is critical to reduce the rate of adverse events. We review the current evidence on sex-specific differences in the utilization and outcomes of treatments for AF, including rate-control and rhythm-control strategies, and stroke-prevention therapy. In addition, we provide a critical evaluation of potential disparities and biases in health-care use that might be associated with differences in the outcomes between women and men. We underscore current knowledge gaps that need to be addressed in future studies to improve the management of AF in women. In particular, we suggest several strategies to produce high-quality evidence from randomized clinical trials for women with AF.

Female Sex, Time in Therapeutic Range, and Clinical Outcomes in Atrial Fibrillation Patients Taking Warfarin

BACKGROUND AND PURPOSE

Female patients have higher risk for stroke than male patients in nonanticoagulated atrial fibrillation patients, but limited data are available on sex differences in stroke and bleeding outcomes among patients with anticoagulated atrial fibrillation on warfarin, especially in relation to quality of anticoagulation control, as reflected by the time in therapeutic range (TTR).

METHODS

We investigated adverse outcomes in females (n=791) and males (n=1501) among 2292 patients with atrial fibrillation taking warfarin arm in the AMADEUS (Evaluating the Use of SR34006 Compared to Warfarin or Acenocoumarol in Patients With Atrial Fibrillation) trial.

RESULTS

The combined end point of cardiovascular death and stroke/systemic embolism (SSE) was similar in females versus males. There was no sex differences in either cardiovascular death or SSE. Compared with males, females had a lower risk of major bleeding (hazard ratio, 0.39; 95% confidence interval, 0.18-0.87; P=0.02). No differences were seen in mortality and stroke outcomes between females and males either in the prespecified age subgroups or in relation to TTR categories. TTR was negatively correlated with any clinically relevant bleeding in both females (r=-0.86; P=0.03) and males (r=-0.94; P=0.005). On Cox regression, TTR (but not female sex) emerged as an independent predictor for combined cardiovascular death/SSE and clinically relevant bleeding events.

CONCLUSION

Anticoagulated female patients with atrial fibrillation had a similar rate of cardiovascular death and SSE, but a lower risk of major bleeding, compared with males. TTR (but not female sex) was an independent predictor for combined cardiovascular death and SSE and clinically relevant bleeding events.

Gender Differences of Thromboembolic Events in Atrial Fibrillation

Atrial fibrillation (AF) is the most common clinically relevant arrhythmia and increases the risk of thromboembolism and stroke; however, these risks are not the same for women and men. This review examines the evidence and clinical significance of increased thromboembolic risk in women with AF. The balance of results from over 30 recent studies suggests that female gender is an independent stroke risk factor in AF, and the inclusion of female gender in stroke risk stratification models, such as CHA2DS2-VASc, has improved risk assessment. Reasons for the increased thrombogenicity in women remain incompletely elucidated, but biological factors including increased hypertension, renal dysfunction, and hyperthyroidism in female patients with AF; cardiovascular remodeling; increased hypercoagulability, and estrogen hormone replacement therapy in women have been proposed. More importantly, gender differences exist in medical management of patients with AF, and compared with men, women have been found to have greater thromboembolic risk when not on anticoagulants, but may benefit from greater risk reduction when systemically anticoagulated. In conclusion, increased clinician awareness of these gender differences may help to improve the management of patients with AF.

Relationship of Age With Stroke and Death in Anticoagulated Patients With Nonvalvular Atrial Fibrillation

Background and Purpose—

The prevalence of atrial fibrillation increases with age, but age-specific data on the incidence of stroke and death in anticoagulated patients with atrial fibrillation are more limited, particularly with regard to comparisons of relative risks of clinical outcomes between the different age strata in relation to quality of anticoagulation control among warfarin users.

Methods—

We investigated the incidence of adverse outcomes between tertiles of age groups (age, <67 [n=722]; age, 67–74 [n=747]; and age, ≥75 [n=824]) in 2293 patients with atrial fibrillation participating in warfarin arm in the AMADEUS (Evaluating the Use of SR34006 Compared to Warfarin or Acenocoumarol in Patients With Atrial Fibrillation) trial. The average time in therapeutic range was calculated as a measure of anticoagulation control and related to clinical outcomes.

Results—

Absolute rates for stroke/systemic embolism (SSE), cardiovascular death, or any clinically relevant bleeding increased with increasing age strata. The combined end point of cardiovascular death and SSE was the highest in the top tertile (adjusted hazard ratio, 2.63; 95% confidence interval, 1.23–5.63) compared with the middle and lowest tertiles ( P for trend=0.01). For bleeding, there was no significant difference in relative risks between the age strata ( P for trend=0.55 in the warfarin group and in the warfarin group with time in therapeutic range ≥60%, P for trend=0.60). The quality of anticoagulation control (time in therapeutic range) significantly correlated with any clinically relevant bleeding ( r =−0.91; P <0.001) and cardiovascular death/SSE rates ( r =−0.76; P =0.01).

Conclusions—

Elderly patients with atrial fibrillation have higher absolute risks of cardiovascular death, SSE, and bleeding, but relative risks of clinically relevant bleeding are not significantly different with increasing age strata. A significant inverse relationship between time in therapeutic range and bleeding and cardiovascular death/SSE emphasizes the importance of good quality anticoagulation control.

Clinical outcomes in patients with atrial fibrillation according to sex during anticoagulation with apixaban or warfarin: a secondary analysis of a randomized controlled trial

AIM

To assess clinical outcomes, efficacy, and safety according to sex during anticoagulation with apixaban compared with warfarin in patients with atrial fibrillation.

METHODS AND RESULTS

Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) was a randomized, double-blind, placebo-controlled, multicentre trial that included 11 785 (64.7%) men and 6416 (35.3%) women with atrial fibrillation or flutter randomized to receive either warfarin or apixaban. The primary efficacy endpoint was stroke or systemic embolism; secondary efficacy endpoints were death from any cause and cardiovascular death. The primary safety endpoint was major bleeding; secondary safety endpoints were a composite of major bleeding and non-major clinically relevant bleeding. The risk of stroke or systemic embolism was similar in women vs. men [adjusted hazard ratio (adjHR): 0.91; 95% confidence interval (CI): 0.74-1.12; P = 0.38]. However, among patients with history of stroke or transient ischaemic attack, women had a lower risk of recurrent stroke compared with men (adjHR: 0.70; 95% CI: 0.50-0.97; P = 0.036). Women also had a lower risk of all-cause death (adjHR: 0.63; 95% CI: 0.55-0.73; P < 0.0001) and cardiovascular death (adjHR: 0.62; 95% CI: 0.51-0.75; P < 0.0001), and a trend towards less major bleeding (adjHR: 0.86; 95% CI: 0.74-1.01; P = 0.066) and major or non-major clinically relevant bleeding (adjHR: 0.89; 95% CI: 0.80-1.00; P = 0.049). The efficacy and safety benefits of apixaban compared with warfarin were consistent regardless of sex.

CONCLUSION

In the ARISTOTLE trial, women had a similar rate of stroke or systemic embolism but a lower risk of mortality and less clinically relevant bleeding than men. The efficacy and safety benefits of apixaban compared with warfarin were consistent in men and women.

TRIAL REGISTRATION

ARISTOTLE ClinicalTrials.gov number, NCT00412984.

Gender differences in stroke prevention in atrial fibrillation in general practice: using the GRASP-AF audit tool

BACKGROUND

Women represent a large proportion of patients with atrial fibrillation (AF) and tend to have higher risk of stroke.

AIMS

This study examines gender differences in the utilisation of oral anticoagulation (OAC) and prognosis (i.e. stroke and death) in AF patients in UK general practice.

DESIGN

Retrospective observational study.

METHODS

The Guidance on Risk Assessment and Stroke Prevention in Atrial Fibrillation (GRASP-AF) tool was employed to identify AF patients from 11 general practices in Darlington, England.

RESULTS

Two thousand two hundred and fifty-nine AF patients (mean±SD age 76 ± 12 years; 46% female) were identified. Based on CHA2 DS2 -VASc score 95% of women and 90% of men were at moderate-high risk of stroke. Women with moderate-high risk of stroke were treated with OAC less frequently than men (47% vs. 52%, p = 0.006). Overall rates of stroke and all-cause mortality were higher among women than men (p = 0.02 and p < 0.001). However, there was no significant gender difference in these outcomes in patients receiving OAC (p = 0.52 for stroke, p = 0.18 for death). Among people not receiving OAC where indicated, female gender was associated with an increased risk of stroke before (p = 0.01), and after (p = 0.04), adjustment for stroke risk factors. Women not receiving OAC had a higher risk of death on univariate regression analysis (p = 0.002), but not after adjustment for stroke risk factors (p = 0.53).

CONCLUSION

Women with AF are at higher risk of stroke than men without OAC. The gender-related differences in risk of stroke disappear if OAC is used. Despite this, women are more likely not to receive OAC.

Is health-related quality of life a predictor of hospitalization or mortality among women or men with atrial fibrillation?

BACKGROUND

Little is known about predictors of mortality or hospitalization in women compared with men in patients with atrial fibrillation (AF). Although there are established gender differences in patients with coronary artery disease (CAD), differences have not been established in AF.

OBJECTIVES

The aim of this study was to examine clinical and health-related quality of life (HRQOL) predictors of mortality and 1-year hospitalization in women compared with men with AF.

METHODS

Limited-use data from the National Institutes of Health/National Heart, Lung, and Blood Institute Atrial Fibrillation Follow-up Investigation of Rhythm Management clinical trial provided the sample of 693 patients with AF, 262 women and 431 men. Clinical predictors examined were heart failure (HF), CAD, left ventricular ejection fraction, diabetes, stroke, and age. Predictors of HRQOL included overall HRQOL (Medical Outcomes Study Short Form-36 physical [PCS] and mental component scores) and cardiovascular HRQOL using Quality of Life Index-Cardiac Version.

RESULTS

Mortality did not differ (women, 11.4%; men, 14.5%; χ(2)1 = 0.437, P = .509) according to gender, with mean 3.5-year follow-up. Different variables independently predicted mortality for women and men. For women, diabetes (hazard ratio [HR], 3.415; P = .003), HF (HR, 2.346; P = .027), stroke (HR, 2.41; P = .032), and age (HR, 1.117; P = .002), and for men, CAD (HR, 1.914; P = 02), age (HR, 1.103, P = < .001), worse PCS (HR, 1.089, P = .001), and worse Quality of Life Index-Cardiac Version score (HR, 1.402, P = .025) independently predicted mortality.One-year hospitalization (women, 38.9%; men, 36.4%) did not differ by gender (χ(2)1 = 0.914, P = .339). Different variables independently predicted 1-year hospitalization-for women: diabetes (odds ratio [OR], 2.359; P = .022), worse PCS (OR, 1.070; P = .003), and rhythm control trial arm (OR, 2.111; P = .006); for men: HF (OR, 2.072; P = .007), worse PCS (OR, 1.045; P = .019), living alone (OR, 1.913; P = .036), and rhythm control trial arm (OR, 2.113; P < .001).

CONCLUSION

Only clinical status predicted mortality among women; HRQOL and clinical status predicted mortality among men. Both clinical and HRQOL variables predicted hospitalization for women and men. Increased monitoring of HRQOL and interventions designed to target the clinical and HRQOL predictors could impact mortality and hospitalization. Nursing interventions may prove effective for modifying most of the predictors of mortality and hospitalization for women and men with AF.

Burden of stroke in women

Stroke is the fifth cause of death in the United States and the first cause of disability. While reductions in stroke mortality have occurred, stroke remains a significant burden in women. In addition to traditional cardiovascular risk factors, there are specific risk factors in women that need to be addressed to further reduce deaths in women from stroke. Atrial fibrillation is common in women and needs proper evaluation for anticoagulation for risk reduction. Stroke in women remains a serious cause of preventable deaths, disability, and cost. Implementation of the new guidelines for stroke prevention in women is critical for reducing the burden of stroke in women.

Does sex affect anticoagulant use for stroke prevention in nonvalvular atrial fibrillation? The prospective global anticoagulant registry in the FIELD-Atrial Fibrillation

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.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01090362.

Gender differences in stroke, mortality, and hospitalization among patients with atrial fibrillation: A systematic review

OBJECTIVE

To conduct a systematic review of gender differences in stroke, mortality, and hospitalization for patients with atrial fibrillation and/or flutter (AF/Afl).

METHODS

Full texts, published, peer-reviewed, English language articles from 1999 through July 2014 were examined. Articles with populations of patients with AF/Afl were included if they conducted longitudinal analysis of any of three outcomes: stroke, mortality, and hospitalization, and reported or compared at least one of the outcomes according to gender.

RESULTS

Seventeen articles were included: sixteen on stroke, nine on mortality, and one on hospitalization. In nine articles women had more strokes (RRs 0.89-1.9). Findings about gender differences in mortality (RRs 0.69-2.8) and hospitalizations were equivocal.

CONCLUSIONS

Few articles examine differences in outcomes between men and women with AF/Afl. Given the prevalence of AF/Afl and health care costs it is vital to determine gender differences to evaluate appropriate therapies to decrease stroke, mortality, and hospitalizations.

Bridging the gender gap in atrial fibrillation

Women have a similar lifetime prevalence of non-valvular atrial fibrillation (NVAF) compared with that of men. Given the significant morbidity and potential mortality associated with NVAF, it is crucial to understand gender differences with NVAF. Women can be more symptomatic than men. Despite a higher baseline stroke risk, they are less likely to be on anticoagulation. Women have a greater risk of thromboembolism and a similar rate of bleeding risk compared with men on anticoagulation. Initial experience suggests that novel oral anticoagulants have similar safety and efficacy profile in men and women. Although women can have more adverse reactions from antiarrhythmic therapies, they are often referred later than men for ablation. As a group, a mitigating factor in ablation referral is that women also have a higher incidence of procedural complications from catheter ablation. This review summarizes the available literature highlighting significant gender-based differences and also highlights areas for research to improve NVAF outcomes in women.

Sex differences in patients receiving anticoagulant therapy for venous thromboembolism

In patients with venous thromboembolism (VTE), the outcome during the course of anticoagulant therapy may differ according to the patient's sex. We used the RIETE (Registro Informatizado Enfermedad TromboEmbólica) database to compare the rate of VTE recurrences, major bleeding, and mortality due to these events according to sex.As of August 2013, 47,499 patients were enrolled in RIETE, of whom 24,280 (51%) were women. Women were older, more likely presented with pulmonary embolism (PE), and were more likely to have recent immobilization but less likely to have cancer than men. During the course of anticoagulation (mean duration: 253 d), 659 patients developed recurrent deep vein thrombosis (DVT), 576 recurrent PE, 1368 bled, and 4506 died. Compared with men, women had a lower rate of DVT recurrences (hazard ratio [HR]: 0.78; 95% confidence interval [CI]: 0.67-0.91), a similar rate of PE recurrences (HR: 0.98; 95% CI: 0.83-1.15), a higher rate of major bleeding (HR: 1.21; 95% CI: 1.09-1.35), and higher mortality due to PE (HR: 1.24; 95% CI: 1.04-1.47). On multivariable analysis, any influence of sex on the risk for recurrent DVT (HR: 0.88; 95% CI: 0.75-1.03), major bleeding (HR: 1.10; 95% CI: 0.98-1.24), or fatal PE (HR: 1.01; 95% CI: 0.84-1.22) was no longer statistically significant.In conclusion, women had fewer DVT recurrences and more bleeds than men during the course of anticoagulation. These differences were not due to sex, but very likely to other patient characteristics more common in female patients and differences in treatment choice.

Gender differences in cardiovascular therapy: focus on antithrombotic therapy and percutaneous coronary intervention

The epidemiology of coronary artery disease (CAD) differs between women and men: female cardiac patients are older and have poorer risk profiles than their male counterparts. This results in a preferential exclusion of women from participation in clinical trials, reducing their power to detect differences in performance of cardiovascular therapies in women. In general, all the antiplatelet and anticoagulant medications used in cardiac patients are equally effective in men and women, although women tend to experience a higher relative benefit due to their poorer risk profile. In particular, women with CAD benefit the most from interventional treatment combined with modern antithrombotic drugs. No gender-related differences in the reduction of thromboembolic risk with more potent antithrombotic drugs have been reported. On the other hand, a clear trend to a higher incidence of bleeding complications has been consistently reported in women, which might be related to a more frequent over-dosage of antithrombotic treatment in women than in men. Women are therefore one of the subgroups that might benefit the most from careful dose adjustment of available antithrombotic drugs. However, the development of a gender-based dosage guideline remains an unmet need in cardiology.

Measures of vitamin K antagonist control reported in atrial fibrillation and venous thromboembolism studies: a systematic review

OBJECTIVE

To aid trialists, systematic reviewers and others, we evaluated the degree of standardisation of control measure reporting that has occurred in atrial fibrillation (AF) and venous thromboembolism (VTE) studies since 2000; and attempted to determine whether the prior recommendation of reporting ≥2 measures per study has been employed.

DESIGN

Systematic review.

SEARCH STRATEGY

We searched bibliographic databases (2000 to June 2013) to identify AF and VTE studies evaluating dose-adjusted vitamin K antagonists (VKAs) and reporting ≥1 control measure. The types of measures reported, proportion of studies reporting ≥2 measures and mean (±SD) number of measures per study were determined for all studies and compared between subgroups.

DATA EXTRACTION

Through the use of a standardised data extraction tool, we independently extracted all data, with disagreements resolved by a separate investigator.

RESULTS

148 studies were included, 57% of which reported ≥2 control measures (mean/study=2.13±1.36). The proportion of time spent in the target international normalised ratio range (TTR) was most commonly reported (79%), and was frequently accompanied by time above/below range (52%). AF studies more frequently reported ≥2 control measures compared with VTE studies (63% vs 37%; p=0.004), and reported a greater number of measures per study (mean=2.36 vs 1.53; p<0.001). Observational studies were more likely to provide ≥2 measures compared with randomised trials (76% vs 33%; p<0.001) and report a greater number of measures (mean=2.58 vs 1.63; p<0.001). More recent studies (2004-2013) reported ≥2 measures more often than older (2000-2003) studies (59% vs 35%; p=0.05) and reported more measures per study (mean=2.23 vs 1.48; p=0.02).

CONCLUSIONS

While TTR was often utilised, studies reported ≥2 measures of VKA control only about half of the time and lacked consistency in the types of measures reported. A trend towards studies reporting greater numbers of VKA control measures over time was observed over our review time horizon, particularly, with AF and observational studies.

Modification of outcomes with aspirin or apixaban in relation to female and male sex in patients with atrial fibrillation: a secondary analysis of the AVERROES study

BACKGROUND AND PURPOSE

The main objective of the present analysis was to assess the effect of treatment with aspirin compared with apixaban on ischemic stroke and major bleeding in women compared with men. Female patients with atrial fibrillation are at increased stroke risk compared with male patients, and the underlying reasons for higher risk are uncertain.

METHODS

Ancillary analysis of the Apixaban Versus Acetylsalicylic Acid [ASA] to Prevent Stroke in Atrial Fibrillation Patients Who Have Failed or Are Unsuitable for Vitamin K Antagonist Treatment (AVERROES) trial, comparing aspirin and apixaban, focused on sex differences. Mean follow-up was 1.1 years.

RESULTS

Women compared with men tended to be older (aspirin, 71.8 versus 68.8 years; apixaban, 71.4 versus 68.6 years), with a higher proportion of those aged≥75 years. Also, women had less peripheral artery disease (aspirin, 2.4% versus 3.7%; apixaban, 1.4% versus 3.0%), more heart failure, and higher mean CHADS2 (congestive heart failure, hypertension, age of 75 years or older, diabetes [1 point each], stroke or transient ischemic attack [2 points]) scores (aspirin, 2.2 versus 2.0; apixaban, 2.1 versus 2.0). Women compared with men had higher ischemic stroke rates (aspirin, 3.99% versus 2.28%; apixaban, 1.55% versus 0.82%) but similar bleeding rates (aspirin, 1.29% versus 1.22%; apixaban, 1.15% versus 1.36%). The relative effect of apixaban compared with aspirin was similar in men and women for both ischemic stroke (women, 3.99% versus 1.55%; hazard ratio, 0.39; 95% confidence interval, 0.23-0.64; men, 2.28% versus 0.82%; hazard ratio, 0.36; 95% confidence interval, 0.19-0.63; Pint=0.84) and major bleeding (women, 1.29% versus 1.15%; hazard ratio, 1.15; 95% confidence interval, 0.59-2.23; men, 1.36% versus 1.22%; hazard ratio, 1.13; 95% confidence interval, 0.64-2.02; Pint=0.96).

CONCLUSIONS

Female patients with atrial fibrillation had higher ischemic stroke rates compared with male patients, but the relative effects of apixaban compared with aspirin on both ischemic stroke and bleeding were similar in men and women.

Efficacy and safety of rivaroxaban compared with warfarin among elderly patients with nonvalvular atrial fibrillation in the Rivaroxaban Once Daily, Oral, Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF)

BACKGROUND

Nonvalvular atrial fibrillation is common in elderly patients, who face an elevated risk of stroke but difficulty sustaining warfarin treatment. The oral factor Xa inhibitor rivaroxaban was noninferior to warfarin in the Rivaroxaban Once Daily, Oral, Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF). This prespecified secondary analysis compares outcomes in older and younger patients.

METHODS AND RESULTS

There were 6229 patients (44%) aged ≥75 years with atrial fibrillation and ≥2 stroke risk factors randomized to warfarin (target international normalized ratio=2.0-3.0) or rivaroxaban (20 mg daily; 15 mg if creatinine clearance <50 mL/min), double blind. The primary end point was stroke and systemic embolism by intention to treat. Over 10 866 patient-years, older participants had more primary events (2.57% versus 2.05%/100 patient-years; P=0.0068) and major bleeding (4.63% versus 2.74%/100 patient-years; P<0.0001). Stroke/systemic embolism rates were consistent among older (2.29% rivaroxaban versus 2.85% warfarin per 100 patient-years; hazard ratio=0.80; 95% confidence interval, 0.63-1.02) and younger patients (2.00% versus 2.10%/100 patient-years; hazard ratio=0.95; 95% confidence interval, 0.76-1.19; interaction P=0.313), as were major bleeding rates (≥75 years: 4.86% rivaroxaban versus 4.40% warfarin per 100 patient-years; hazard ratio=1.11; 95% confidence interval, 0.92-1.34; <75 years: 2.69% versus 2.79%/100 patient-years; hazard ratio=0.96; 95% confidence interval, 0.78-1.19; interaction P=0.336). Hemorrhagic stroke rates were similar in both age groups; there was no interaction between age and rivaroxaban response.

CONCLUSIONS

Elderly patients had higher stroke and major bleeding rates than younger patients, but the efficacy and safety of rivaroxaban relative to warfarin did not differ with age, supporting rivaroxaban as an alternative for the elderly.

Sex differences in stroke prevention in atrial fibrillation in French primary care. Results of the AFIGP (Atrial Fibrillation In General Practice) database

BACKGROUND AND OBJECTIVES

Most of the French patients diagnosed with atrial fibrillation (AF) are managed by general practitioners (GPs). The objective was to evaluate stroke prevention in AF patients ahead of the arrival of the non vitamin K oral anticoagulant in France.

METHODS

A cross-sectional study using a French GPs database of all patients with a diagnosis of AF consulting their GP between July-2010 and June-2011. Multivariate analyses were used to identify determinants of prevention prescription.

RESULTS

Among 15,623 AF patients, 42.5 % were ≥75 years and 40.5 % women, 59.2 % had hypertension, 17.2 % diabetes, 11.4 % heart failure, 4.9 % stroke history. CHADS2 score was ≥1 for 83.1 % and ≥2 for 50.9 % of patients (CHA2DS2-VASc score ≥1 for 93.7 % and ≥2 for 82.3 %). Antithrombotic therapies were vitamin K antagonists (VKA) for 50.7 % of patients, followed by aspirin for 19.9 %, clopidogrel ± aspirin for 4.3 % and none for 25.1 %. For patients with CHADS2 scores ≥1, 73.3 % received an antithrombotic and for those with CHADS2 scores ≥2, 54.9 % were treated by a VKA. An age-stratified multivariate analysis showed that women had an odds ratio to be treated with VKA compared to 0.83 (95 % CI: 0.72-0.95) and 0.66 (95 % CI: 0.59-0.74) when aged <75 years and ≥75 years, respectively.

CONCLUSIONS

Most AF patients followed by French GPs required stroke prevention according to European guidelines, but many of them did not receive the recommended antithrombotic treatment. Women over 75 were a third less likely to be treated with recommended anticoagulants than men of similar age.

Impact of gender on the prognosis of patients with nonvalvular atrial fibrillation

Treatment guidelines for atrial fibrillation (AF) used in Western countries describe female gender as a risk factor for thromboembolic events in patients with nonvalvular AF (NVAF). The present study aimed to determine the impact of gender on prognosis of Japanese patients with NVAF. A subanalysis of 7,406 patients with NVAF (mean age 70 years) who were followed-up prospectively for 2 years was performed using data from the J-RHYTHM registry. The primary end points were thromboembolic events, major hemorrhaging, total mortality, and cardiovascular mortality. Compared with male subjects (n = 5,241), female subjects (n = 2,165) were older and displayed greater prevalences of paroxysmal AF, heart failure, and hypertension but less prevalences of diabetes, previous cerebral infarction, and coronary artery disease. Male and female patients had mean CHADS2 (Congestive heart failure, Hypertension, Age of 75 years or more, Diabetes mellitus and prior Stroke or transient ischemic attack) scores of 1.6 and 1.8, respectively (p <0.001). Warfarin was given to 87% of male patients and 86% of female patients (p = 0.760), and the 2 genders displayed similar mean international normalized ratio of prothrombin time values at baseline (1.91 vs 1.90, respectively, p = 0.756). Multivariate logistic regression analysis indicated that male gender was an independent risk factor for major hemorrhaging (odds ratio 1.59, 95% confidence interval 1.05 to 2.40, p = 0.027) and all-cause mortality (odds ratio 1.78, 95% confidence interval 1.25 to 2.55, p <0.002) but not for thromboembolic events (odds ratio 1.24, 95% confidence interval 0.83 to 1.86, p = 0.297) or cardiovascular mortality (odds ratio 0.96, 95% confidence interval 0.56 to 1.66, p = 0.893). In conclusion, female gender is not a risk factor for thromboembolic events among Japanese patients with NVAF who were treated mostly with warfarin. However, male gender is a risk factor for major hemorrhaging and all-cause mortality.

Meta-analysis of gender differences in residual stroke risk and major bleeding in patients with nonvalvular atrial fibrillation treated with oral anticoagulants

Studies comparing gender-specific outcomes in patients with atrial fibrillation (AF) have reported conflicting results. Gender differences in cerebrovascular accident/systemic embolism (CVA/SE) or major bleeding outcomes with novel oral anticoagulant (NOAC) use are not known. The goal of this analysis was to perform a systematic review and meta-analysis evaluating gender differences in residual risk of CVA/SE and major bleeding outcomes in patients with nonvalvular AF treated with either warfarin or NOAC. Sixty-four randomized studies were identified using keywords "gender," "AF," and "CVA." Using the Preferred Reporting Items for Systemic Reviews and Meta-analysis method, 6 studies met criteria for inclusion in this meta-analysis. CVA/SE and major bleeding outcomes were separately analyzed in cohorts receiving warfarin and NOAC agents, comparing men with women. Women with AF taking warfarin were at a significantly greater residual risk of CVA/SE compared with men (odds ratio 1.279, 95% confidence interval 1.111 to 1.473, Z = -3.428, p = 0.001). No gender difference in residual risk of CVA/SE was noted in patients with AF receiving NOAC agents (odds ratio 1.146, 95% confidence interval 0.97 to 1.354, p = 0.109). Major bleeding was less frequent in women with AF treated with NOAC. In conclusion, women with AF treated with warfarin have a greater residual risk of CVA/SE and an equivalent major bleeding risk, whereas those treated with NOAC agents deemed superior to warfarin are at equivalent residual risk of CVA/SE and less major bleeding risk compared with men. These results suggest an increased net clinical benefit of NOAC agents compared with warfarin in treating women with AF.

Female sex as an independent risk factor for stroke in atrial fibrillation: possible mechanisms

Atrial fibrillation (AF) is an independent risk factor for thromboembolism and stroke. Women with AF are at a higher overall risk for thromboembolic stroke when compared to men with AF. Recent evidence suggests that female sex, after adjusting for stroke risk profile and sex differences in utilisation of anticoagulation, is an independent stroke risk factor in AF. The inclusion of female sex has improved the accuracy of the CHADS2 stroke risk stratification schema (Congestive heart failure, Hypertension, Age 75 years or greater, Diabetes mellitus, and prior Stroke or TIA). The newly revised and validated schema, CHA2DS2-VASc, dichotomises age and incorporates female sex and vascular disease history. The pathophysiological mechanisms to explain this increased risk in women are not well understood. According to Virchow's triad, thrombosis that leads to stroke in AF should arise from three co-existing phenomena: structural abnormalities, blood stasis, and a hypercoagulable state. Herein, we explore the sex differences in the biological processes that lead to thrombus formation as applied to Virchow's Triad. The objective of this review is to describe the potential mechanisms behind the increased risk of stroke in AF associated with female sex.