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

Women have less progression of paroxysmal atrial fibrillation: data from the RACE V study

BACKGROUND

Sex differences in atrial fibrillation (AF) are observed in terms of comorbidities, symptoms, therapies received, AF progression and cardiovascular complications.

METHODS

We assessed the differences in prevalence and the determinants of AF progression, as well as the clinical characteristics and quality of life (QoL), between women and men with paroxysmal AF included in the RACE V (Reappraisal of Atrial Fibrillation: Interaction between hyperCoagulability, Electrical remodeling, and Vascular Destabilisation in the Progression of AF) study. At baseline, extensive phenotyping was done. To assess AF progression, implantable loop recorder (ILR) monitoring was used throughout follow-up. AF progression was defined as (1) progression to persistent or permanent AF or (2) progression of paroxysmal AF (>3% burden increase).

RESULTS

417 patients were included, 179 (43%) of whom were women. Women were older (median 67 years vs 63 years, p<0.001), less often had coronary artery disease (n=11 (6%) vs n=36 (16%), p=0.003), had more obesity (n=57 (32%) vs n=50 (21%), p=0.013), had less epicardial and pericardial fat (median 144 (interquartile range [IQR] 94-191) mL vs 199 (IQR 146-248) mL, p<0.001; and median 89 (ICQ 61-121) mL vs 105 (IQR 83-133) mL, p<0.001, respectively) and had more impaired left atrial function. The median follow-up was 2.2 (1.6-2.8) years. 51 of 417 patients (5.5% per year) showed AF progression (15/179 (8.4%) women and 36/238 (15.1%) men, p=0.032). Multivariable analysis showed tissue factor pathway inhibitor, N-terminal prohormone brain natriuretic peptide (NT-proBNP) and PR interval being associated with AF progression in women and factor XIIa:C1 esterase, NT-proBNP and proprotein convertase subtilisin/kexin type 9 in men. QoL was not different between sexes.

CONCLUSION

Despite older age, the incidence of AF progression was lower in women. Parameters associated with AF progression varied in part between sexes, suggesting different underlying pathophysiological mechanisms.

Sex Differences in Thrombin Generation in Patients with Acute Ischemic Stroke

Sex differences in stroke exist, including variation in stroke risk and outcome. Differences in thrombin generation may contribute to this variation between females and males. To examine this, we assessed sex differences in thrombin generation between females and males with acute ischemic stroke and the relationship to blood cell gene expression. In 97 patients with acute ischemic stroke, thrombin generation was measured by thrombin generation assay. Blood cell gene expression was measured by microarray. Differences in thrombin generation between sexes were identified and the relationship to blood cell gene expression examined. Genes associated with sex differences in thrombin generation were analyzed by functional pathway analysis. Females and males had similar overall capacity to generate thrombin. The peak thrombin generated in females was 468.8 nM (SD 91.6), comparable to males (479.3nM;SD 90.8; p = 0.58). Lag time, time to peak thrombin, and endogenous thrombin potential were also similar between females and males. While overall thrombin generation was comparable between females and males with stroke, differences in genes that promote this thrombin generation exist. Females with high peak thrombin had an increase in genes that promote thrombosis, and platelet activation. In contrast, males with high peak thrombin had a decrease in genes involved in thrombus degradation. Females and males with acute ischemic stroke have similar capacity to generate thrombin, however, differences may exist in how this thrombin generation is achieved, with females having increased thrombin signaling, and platelet activation, and males having decreased thrombus degradation. This suggests regulatory differences in thrombosis may exist between females and males that may contribute to sex differences in stroke.

Is the association between cognitive disease progression and atrial fibrillation modified by sex?

INTRODUCTION

It is unclear if sex differences exist in cognitive disease progression in mild cognitive impairment (MCI) and dementia associated with atrial fibrillation (AF).

METHODS

Using a variety of statistical methods, we examined sex differences between AF and neuropsychological tests and cognitive disease progression, using the National Alzheimer's Coordinating Center data (N = 43,630).

RESULTS

AF is associated with higher odds of dementia (odds ratio [OR] 3.00, 95% confidence interval [CI] [1.22, 7.37] in women and MCI in women (OR 3.43, 95% CI [1.55, 7.55]) versus men. Women with AF and normal baseline cognition had a higher risk of disease progression (hazard ratio [HR] 1.26, 95% CI [1.06, 1.50]) from normal to MCI and from MCI to vascular dementia (HR3.27, 95% CI [1.89, 5.65]) than men with AF or men and women without AF.

DISCUSSION

AF was associated with more rapid progression to MCI and dementia in women, but more research is needed to confirm these findings.

Sex-related differences in outcome after left atrial appendage occlusion: Insights from Europe and the EWOLUTION registry

BACKGROUND

Women with atrial fibrillation (AF) generally experience worse symptoms, poorer quality of life, and have a higher risk of stroke and death. There is limited availability of sex-related differences regarding left atrial appendage occlusion (LAAO).

AIMS

The aim of this study was to evaluate the sex-related differences in patients undergoing LAAO in EWOLUTION.

METHODS

A total of 1025 patients scheduled for elective LAAO therapy employing the WATCHMAN Gen 2.5 prospectively consented for participation; 1005 patients received a successful implant and were followed for 2 years. As we detected sex-related differences in baseline data we performed a propensity score matching. The primary endpoint is a combined endpoint of survival free from mortality, major bleeding, ischemic stroke, transitory ischemic attack (TIA) and systemic embolization (SE) up to 2-year clinical follow-up. Secondary Endpoints were periprocedural data and overall 2-year survival.

RESULTS

Women were older but had less often vascular disease and hemorrhagic stroke. There was no sex-related significant difference after LAAO at 2 years in the combined endpoint of survival free from mortality, major bleeding, ischemic stroke, TIA, and SE (female vs. male: 79% vs.76%, p = 0.24) or in overall survival (female vs. male: 85% vs. 82%, p = 0.16). Procedural data showed a higher sealing rate after the implantation in women (complete sealing female 94% vs. male 90%, p = 0.033), significantly more pericardial effusions (female 1.2% vs. male 0.2%, p = 0.031) and a similar periprocedural risk profile.

CONCLUSIONS

Females undergoing LAAO differ in various baseline variables, but after adjustment, we observed similar safety and efficacy of LAAO with no significant difference in long-term outcomes between women and men.

Initial In-Hospital Visit-to-Visit Heart Rate Variability Is Associated with Higher Risk of Atrial Fibrillation in Patients with Acute Ischemic Stroke

BACKGROUND

To evaluate the association between the visit-to-visit heart rate variability and the risk of atrial fibrillation (AF) in acute ischemic stroke (AIS).

METHODS

We analyzed the data of 8179 patients with AIS. Patients without AF on 12-lead electrocardiography underwent further 24 h Holter monitoring. They were categorized into four subgroups according to the visit-to-visit heart rate variability expressed as the coefficient of variation in heart rate (HR-CV). Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using the HR-CV < 0.08 subgroup as a reference.

RESULTS

The adjusted OR of paroxysmal AF was 1.866 (95% CI = 1.205-2.889) for the HR-CV ≥ 0.08 and <0.10 subgroup, 1.889 (95% CI = 1.174-3.038) for the HR-CV ≥ 0.10 and <0.12 subgroup, and 5.564 (95% CI = 3.847-8.047) for the HR-CV ≥ 0.12 subgroup. The adjusted OR of persistent AF was 2.425 (95% CI = 1.921-3.062) for the HR-CV ≥ 0.08 and <0.10 subgroup, 4.312 (95% CI = 3.415-5.446) for the HR-CV ≥ 0.10 and <0.12 subgroup, and 5.651 (95% CI = 4.586-6.964) for the HR-CV ≥ 0.12 subgroup.

CONCLUSIONS

HR-CV can facilitate the identification of patients with AIS at a high risk of paroxysmal AF.

Gender Differences in Atrial Fibrillation: From the Thromboembolic Risk to the Anticoagulant Treatment Response

Atrial fibrillation (AF) is the most common cardiac arrhythmia associated with an increased thromboembolic risk. The impact of the female sex as an independent risk factor for thromboembolic events in AF is still debated. Background and Objectives: The aim of this review is to evaluate the gender-related differences in cardioembolic risk and response to anticoagulants among AF patients. Materials and Methods: The PubMed database is used to review the reports about gender differences and thromboembolic risk in atrial fibrillation. Results: Non-vitamin K oral anticoagulants (NOACs) represent the gold standard for thromboembolic risk prevention in patients with non-valvular atrial fibrillation (NVAF). Despite a similar rate of stroke and systemic embolism (SE) among men and women in NOACs or vitamin K antagonists (VKAs) treatment, the use of NOACs in AF women is associated with a lower risk of intracranial bleeding, major bleeding, and all-cause mortality than in men. Conclusions: The female sex can be defined as a stroke risk modifier rather than a stroke risk factor since it mainly increases the thromboembolic risk in the presence of other risk factors. Further studies about the efficacy and safety profile of NOACs according to sex are needed to support clinicians in performing the most appropriate and tailored anticoagulant therapy, either in male or female AF patients.

Sex differences in clinical profile, management, and outcomes of patients hospitalized for atrial fibrillation in the United States

AIMS

This study aimed to investigate the impact of sex on the clinical profile, utilization of rhythm control therapies, cost of hospitalization, length of stay, and in-hospital mortality in patients admitted for atrial fibrillation (AF) in the United States.

METHODS AND RESULTS

We used data from the Nationwide Inpatient Sample for the year 2018. Regression analysis was performed to investigate differences between men and women. A P-value ≤ 0.05 was considered significant. We included 82592 patients with a primary diagnosis of of AF 50.8% women. Women were significantly older (mean age 74 vs. 67 years, P < 0.001) and had a higher CHA2DS2-VASc score (median 4 vs. 2, P < 0.001) than men. Women had relatively higher in-hospital mortality (0.9% vs. 0.8%, P = 0.070); however, after adjustment for known risk factors female sex was no longer a predictor of mortality (P = 0.199). In sex-specific regression analyses, increased age, chronic obstructive pulmonary disease, previous stroke, heart failure, and chronic kidney disease were risk factors for in-hospital mortality in both sexes, vascular disease only in women, and race and alcohol abuse only in men. After adjusting for potential confounders, female sex was associated with lower likelihood of receiving catheter ablation [adjusted odds ratio (aOR) 0.69, 95% confidence interval (CI) 0.64-0.74] and electrical cardioversion (aOR 0.69, 95% CI 0.67-0.72), and with longer hospitalization (aOR 1.33, 95% CI 1.28-1.37), whereas sex had no influence on hospitalization costs (P = 0.339).

CONCLUSION

There were differences in the risk profile, management, and outcomes between men and women hospitalized for AF. Further studies are needed to explore why women are treated differently regarding rhythm control procedures.

Sex Differences in Efficacy and Safety After Left Atrial Appendage Closure: A 4.3-Year Follow-Up Analysis

Introduction

Women are related to higher stroke risk and poorer outcome after stroke attack in patients with non-valvular atrial fibrillation (NVAF). The sex differences in efficacy and safety after left atrial appendage closure (LAAC) have remained elusive. This retrospective study aimed to investigate the safety, feasibility, and clinical outcomes of LAAC between women and men.

Methods

From 2014 to 2018, 395 patients who underwent LAAC in our center were enrolled in this retrospective study. Baseline clinical characteristics, procedural parameters, and postoperative follow-up data were collected and compared between women and men.

Results

The study included 154 women and 241 men. Compared with men, women were older (68.1 ± 7.9 vs. 64.6 ± 8.8, p < 0.01**), with higher CHA2DS2-VASc score (4.0 ± 1.7 vs. 3.0 ± 1.6, p < 0.01**). During the mean follow-up duration of 1,566 days (4.3 years), there were 39 major adverse cardiovascular events (MACE, including 19 cardiovascular or unexplained deaths, 15 ischemic strokes, and 5 major bleedings) recorded in 34 patients. The overall rate of ischemic stroke was 0.9 per 100 patient-years, and the overall rate of MACE was 2.1 per 100 patient-years. The cardiovascular or unexplained death and major bleeding were comparable between women and men. Compared with men, women had lower rates of ischemic stroke, fatal or disabling ischemic stroke, MACE, and fatal or disabling MACE, but none of them reached statistical differences (HR: 0.361, p = 0.099, HR: 0.429, p = 0.276, HR: 0.600, p = 0.170, and HR: 0.621, p = 0.254, respectively). In the adjusted analyses with multivariate Cox regression models, women had a lower fatal or disabling ischemic stroke rate compared with men (HR: 0.100, p = 0.041).

Conclusion

Left atrial appendage closure was feasible and safe for patients of both genders. The ischemic stroke, cardiovascular or unexplained death, and major bleeding were comparable between women and men. However, women were the independent protective factors against fatal or disabling ischemic stroke after LAAC implantation.

Sex disparities in enrollment and reporting of outcomes by sex in contemporary clinical trials of atrial fibrillation

BACKGROUND

Underrepresentation of females in randomized controlled trials (RCTs) limits generalizability and quality of the evidence guiding treatment of females. This study aimed to measure the sex disparities in participants' recruitment in RCTs of atrial fibrillation (AF) and determine associated factors, and to describe the frequency of outcomes reported by sex.

METHODS

MEDLINE was searched to identify RCTs of AF published between January 1, 2011, and November 20, 2021, in 12 top-tier journals. We measured the enrollment of females using the enrollment disparity difference (EDD) which is the difference between the proportion of females in the trial and the proportion of females with AF in the underlying general population (obtained from the Global Burden of Disease). Random-effects meta-analyses of the EDD were performed, and multivariable meta-regression was used to explore factors associated with disparity estimates. We also determined the proportion of trials that included sex-stratified results.

RESULTS

Out of 1133 records screened, 142 trials were included, reporting on a total of 133 532 participants. The random-effects summary EDD was -0.125 (95% confidence interval [CI] = -0.143 to -0.108), indicating that females were under-enrolled by 12.5 percentage points. Female enrollment was higher in trials with higher sample size (<250 vs. >750, adjusted odds ratio [aOR] 1.065, 95% CI: 1.008-1.125), higher mean participants' age (aOR: 1.006, 95% CI: 1.002-1.009), and lower in trials conducted in North America compared to Europe (aOR: 0.945, 95% CI: 0.898-0.995). Only 36 trials (25.4%) reported outcomes by sex, and of these 29 (80.6%) performed statistical testing of the sex-by-treatment interaction.

CONCLUSION

Females remain substantially less represented in RCTs of AF, and sex-stratified reporting of primary outcomes is infrequent. These findings call for urgent action to improve sex equity in enrollment and sex-stratified outcomes' reporting in RCTs of AF.

Sex-specific differences in adverse outcome events among patients with atrial fibrillation

OBJECTIVE

To assess whether women with atrial fibrillation (AF) have a higher risk of adverse events than men during long-term follow-up since controversial data have been published.

METHODS

In the context of two very similar observational multicentre cohort studies, we prospectively followed 3894 patients (28% women) with previously documented AF for a median of 4.02 (3.00-5.83) years. The primary outcome was a composite of ischaemic stroke, myocardial infarction and cardiovascular death. Secondary outcomes included the individual components of the composite outcome, hospitalisation for heart failure, major and clinically relevant non-major bleeding, stroke or systemic embolism and non-cardiovascular death.

RESULTS

Mean age was 73.1 years in women vs 70.8 years in men. The incidence of the primary endpoint in women versus men was 2.46 vs 3.24 per 100 patient-years, respectively (adjusted HR (aHR) 0.74, 95% CI 0.58 to 0.94; p=0.01). Women died less frequently from cardiovascular (aHR 0.57, 95% CI 0.41 to 0.78; p<0.001) and non-cardiovascular causes (aHR 0.68, 95% CI 0.47 to 0.98; p=0.04). There were no significant sex-specific differences in stroke (incidence 1.05 vs 1.00; aHR 1.02, 95% CI 0.70 to 1.49, p=0.93), myocardial infarction (incidence 0.67 vs 0.72; aHR 0.98, 95% CI 0.61 to 1.57, p=0.94), major and clinically relevant non-major bleeding (incidence 4.51 vs 4.34; aHR 0.95, 95% CI 0.79 to 1.15, p=0.63) or heart failure hospitalisation (incidence 3.28 vs 3.07; aHR 1.06, 95% CI 0.85 to 1.32, p=0.60).

CONCLUSION

In this large study of patients with established AF, women had a lower risk of death than men, but there were no sex-specific differences in other adverse outcomes.

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.

Stroke risk factors and outcomes among hospitalized women with atrial fibrillation

Observational cohort analyses suggest that women with atrial fibrillation (AF) endure a greater burden of stroke. We conducted an analysis of an observational cohort study completed at our tertiary care medical center to assess sex-related differences in cardiovascular risk factors, prescription of antithrombotic therapy, and 90-day outcomes. We analyzed 5000 hospitalized patients with AF: 1888 women and 3112 men. Clinical characteristics of AF, risk of stroke and bleeding, prescription of antithrombotic therapy, and 90-day clinical outcomes, including stroke and all-cause mortality, were compared. We observed a 50% higher relative frequency of stroke in hospitalized women with AF compared with men. While the frequencies of prescription of antithrombotic therapy at discharge were similar, anticoagulation was omitted in 40% of women with AF. The 90-day frequencies of major adverse events and mortality were increased in hospitalized women with AF not prescribed antithrombotic therapy at discharge. Prescription of anticoagulation in women with AF at hospital discharge was associated with a 60% and 40% relative reduction in the odds of mortality and major adverse events at 90 days. In conclusion, women hospitalized with AF have a higher risk of stroke at 90 days compared with men. Anticoagulation at hospital discharge was omitted in 40% of women with AF, but when prescribed, was associated with a reduction in mortality and major adverse events at 90 days, respectively. We analyzed 5000 hospitalized patients with atrial fibrillation (AF) (1888 women and 3112 men) in an observational cohort study completed at our tertiary care medical center to assess sex-related differences in cardiovascular risk factors, prescription of antithrombotic therapy, and 90-day outcomes. We observed a 50% higher relative frequency of stroke in hospitalized women with AF compared with men. The 90-day frequencies of major adverse events and mortality were increased in hospitalized women with AF not prescribed antithrombotic therapy at discharge. Prescription of anticoagulation in women with AF at hospital discharge was associated with a 60% and 40% relative reduction in the odds of mortality and major adverse events at 90 days.

Influence of gender on the clinical outcomes of Asian non-valvular atrial fibrillation patients: insights from the prospective multicentre COOL-AF registry

OBJECTIVE

To determine the effect of gender on clinical outcomes of Asian non-valvular atrial fibrillation patients.

DESIGN

This is a cohort study.

SETTING

27 university and regional hospitals in Thailand.

PARTICIPANTS

Patients with non-valvular atrial fibrillation.

PRIMARY AND SECONDARY OUTCOMES MEASURES

The clinical outcomes were ischaemic stroke/transient ischaemic attack (TIA), major bleeding, intracerebral haemorrhage (ICH), heart failure and death. Follow-up data were recorded every 6 months until 3 years. Differences in clinical outcomes between males and females were determined. Multivariate analysis was performed to assess the effect of gender on clinical outcomes. Survival analysis and log-rank test were performed to determine the time-dependent effect of clinical outcomes, and the difference between males and females. Effect of oral anticoagulant (OAC) on outcomes and net clinical benefit of OAC was assessed. The analysis was performed both for the whole dataset and propensity score matching with multiple imputation.

RESULTS

A total of 3402 patients (mean age: 67.4±11.3 years; 58.2% male) were included. Average follow-up duration 25.7±10.6 months (7192.6 persons-year). Rate of ischaemic stroke/TIA, major bleeding, ICH, heart failure and death were 1.43 (1.17-1.74), 2.11 (1.79-2.48), 0.70 (0.52-0.92), 3.03 (2.64-3.46) and 3.77 (3.33-4.25) per 100 person-years. Females had increased risk for ischaemic stroke/TIA and heart failure and males had increased risk for major bleeding and ICH. Ischaemic stroke/TIA risk in females and major bleeding and ICH risk in males remained even after correction for age, comorbid conditions and anticoagulation treatment. OAC reduced the risk of ischaemic stroke/TIA in males and females, and markedly increased the risk of major bleeding and ICH in males.

CONCLUSIONS

Females had a higher risk of ischaemic stroke/TIA and heart failure, and a lower risk of major bleeding and ICH compared with males. OAC reduced risk of ischaemic stroke/TIA in females, and markedly increased risk of major bleeding and ICH in males.

Women and atrial fibrillation

Atrial fibrillation (AF) remains a growing problem in the United States and worldwide, imposing a high individual and health system burden, including increased resource consumption due to repeated hospitalizations, stroke, dementia, heart failure, and death. This comprehensive review summarizes the most recent data on sex-related differences in risks associated with AF. Women with AF have increased risk of stroke and death compared to men, and possible reasons for this disparity are explored. Women also continue to have worse symptoms and quality of life, and poorer outcomes with stroke prevention, as well as with rate and rhythm control management strategies. Many current rhythm control treatment strategies for AF, including cardioversion and ablation, are used less frequently in women as compared to men, whereas women are more likely to be treated with rate control strategies or antiarrhythmic drugs. Sex differences should be considered in treating women with AF to improve outcomes and women and men should be offered the same interventions for AF. We need to improve the evidence base to understand if variation in utilization of rate and rhythm control management between men and women represents health inequities or appropriate clinical judgement.

Impact of gender: Rivaroxaban for patients with atrial fibrillation in the XANTUS real-world prospective study

BACKGROUND

The XANTUS study (NCT01606995) demonstrated low rates of stroke and major bleeding in patients with atrial fibrillation (AF) receiving rivaroxaban in clinical practice for the prevention of thromboembolic events (N = 6784).

HYPOTHESIS

Because previous real-world studies have not reported gender-dependent responses to rivaroxaban treatment, this sub-analysis of the XANTUS study investigated the effect of gender on outcomes.

METHODS

The centrally adjudicated outcomes were compared between genders. Primary outcomes were major bleeding and all-cause death. Secondary outcomes included symptomatic thromboembolic events. Multivariable Cox regression analysis was performed to assess the effect of risk factors on outcomes between genders.

RESULTS

A total of 2765 female and 4016 male patients were included in the analysis. Baseline characteristics were generally similar. No nominally significant interaction between gender and risk factors for the study outcomes was observed. Rates of major bleeding, all-cause death and symptomatic thromboembolic events in patients with non-valvular AF receiving rivaroxaban for stroke prevention were similar in men and women; no significant differences in risk factors for these outcomes were observed between genders.

CONCLUSIONS

Further research is needed to better characterize the relative importance of different risk factors on outcomes in men vs women and to determine whether gender differences exist in patients treated with non-vitamin K antagonist oral anticoagulants.

Female Sex as a Thromboembolic Risk Factor in the Era of Nonvitamin K Antagonist Oral Anticoagulants

Sex-specific differences have been definitively demonstrated in cardiovascular (CV) diseases. These differences can also impact on the effects of CV therapies. Female sex is recognized as an independent predictor of thromboembolic risk, particularly in older patients. Most of strokes are due to atrial fibrillation (AF). Women affected by AF have higher stroke risk compared to men. The introduction of novel oral anticoagulants (NOACs) for long-term anticoagulation completely changed the anticoagulant therapeutic approach and follow-up of patients affected by nonvalvular atrial fibrillation (NVAF). CHA2DS2-VASc stroke risk scoring in use in the current international guidelines attributes 1 point to “female sex”. Besides, no anticoagulation is indicated for AF female patients without other risk factors. Interestingly, NOACs seem to normalize the differences between males and females both in terms of safety and efficacy, whereas residual higher stroke risk and systemic embolism persist in AF women treated with vitamin K antagonist anticoagulants VKA with optimal time in therapeutic range. Based on the CHA2DS2-VASc score, NOACs represent the preferred choice in NVAF patients. Moreover, complete evaluation of apparently lower risk factor along with concomitant clinical conditions in AF patients appears mandatory, particularly for female patients, in order to achieve the most appropriate anticoagulant treatment, either in male or in female patients. The present review was performed to review sex differences in AF-related thromboembolic risk reported in the literature and possibly highlight current knowledge gaps in prevention and management that need further research.

Atrial fibrillation-related stroke in women: Evidence and inequalities in epidemiology, mechanisms, clinical presentation, and management

Background

Atrial fibrillation (AF) is the most common clinical arrhythmia and one of the major causes of stroke, heart failure, sudden death, and cardiovascular morbidity. Despite substantial advances in (interventional) rhythm control treatment during the last decade, anticoagulation for stroke prevention remains a major component of AF treatment.

Hypothesis

There are important sex‐specific differences in AF‐related stroke, resulting from sex‐specific mechanisms and therapeutic differences.

Methods

This review summarizes available data on sex differences in risk assessment and prevention of stroke and highlights current knowledge gaps in AF‐related stroke mechanisms, prevention and management that warrant further research.

Results

Increased thrombotic risk in women is multifactorial, involving hormonal changes after menopause, structural, endocrine and lifestyle/social factors and their interactions. It is clear from randomized studies that women benefit from anticoagulant treatment and that their bleeding risk is similar to men. Women should therefore receive equivalent treatment to men, based on the validated criteria for anticoagulation therapy. However, women are not represented equally in the large randomized studies and sex‐related information in many fields is lacking.

Conclusions

Female sex is an established risk factor for stroke in AF patients. The evidence for sex‐specific differences in stroke risk assessment and stroke prevention is accumulating. However, the underlying biological mechanisms remain incompletely understood and further studies are required in order to decrease AF‐related morbidity and mortality.

Risk of ischemic stroke and utility of CHA2 DS2 -VASc score in women and men with atrial fibrillation

Background

The magnitude of increased risk of stroke in women with atrial fibrillation (AF) remains uncertain.

Hypothesis

We investigated the risk of ischemic stroke and death in women and men with AF, and the risk associated with individual non‐sex CHA₂DS₂‐VASc risk factors.

Methods

Retrospective cohort study of 231 077 (48.1% women) nonselected patients with AF not receiving oral anticoagulation from 2006 to 2014. Data from cross‐linked national Swedish registers. The outcome was the first occurrence of ischemic stroke or death. Median age was 82 and 75 years in women and men, respectively. Mean follow‐up was 2.5 years.

Results

Hazard ratios, adjusted for non‐sex CHA₂DS₂‐VASc risk factors, for women vs men were 1.53, 95% CI: 1.49‐1.58 for ischemic stroke and 1.24, 95% CI: 1.22‐1.26 for death, respectively. When divided into age groups the differences in ischemic stroke rates between women and men were attenuated. In patients with only one non‐sex CHA₂DS₂‐VASc risk factor allotted 1 point, ischemic stroke rates per 100 person‐years were 1.22 in women (n = 9838) and 1.02 in men (n = 15 609), respectively, P < .006. In both women and men, age of 65 to 74 years was associated with higher ischemic stroke risk compared to other non‐sex CHA₂DS₂‐VASc risk factors allotted 1 point.

Conclusions

The risk of ischemic stroke was 1.5‐fold higher in women compared to men but this association appears to be the result of confounding by age. In the low risk end, the CHA₂DS₂‐VASc risk score underestimates the ischemic stroke risk conferred by age 65 to 74 years, while it overestimates the risk conferred by female sex.

Comparative effectiveness of rivaroxaban versus a vitamin K antagonist in patients with renal impairment treated for non-valvular atrial fibrillation in Germany - A retrospective cohort study

Background

The risk of thromboembolic events is increased in patients with non-valvular atrial fibrillation (NVAF) and renal impairment. The risk of bleeding events is increased if these patients are treated with anticoagulants and further increased in those with active cancer.

Methods

RELOAD, a retrospective database study, assessed the outcomes of patients with NVAF prescribed rivaroxaban versus phenprocoumon. Here, we present a subgroup analysis evaluating effectiveness and safety of rivaroxaban versus phenprocoumon in patients with NVAF and renal impairment. Analyses were additionally stratified by patients with and without evidence of cancer at baseline.

Results

When using the ‘one tablet per day’ definition of estimating drug exposure time, the incidence of the primary endpoint of ischaemic stroke was significantly lower in patients (without evidence of cancer at baseline) receiving rivaroxaban 15 mg or 20 mg once daily versus those receiving phenprocoumon (2.40 vs 3.51 events per 100 patient-years, respectively; hazard ratio [HR] = 0.72, 95% confidence interval [CI] 0.55–0.94, p = 0.015); with the incidence of the primary safety outcome of intracranial haemorrhage being numerically lower (0.57 vs 0.89 events per 100 patient-years, respectively; HR = 0.66, 95% CI 0.38–1.14, p = 0.14). Similar results were observed when using the ‘empirical defined daily dose’ definition to estimate drug exposure time and when including patients with evidence of cancer.

Conclusion

The prescription of rivaroxaban in patients with NVAF and renal impairment was associated with a lower incidence of ischaemic stroke and intracranial haemorrhage versus phenprocoumon in patients without evidence of cancer.

Female Sex Is a Risk Modifier Rather Than a Risk Factor for Stroke in Atrial Fibrillation: Should We Use a CHA2DS2-VA Score Rather Than CHA2DS2-VASc?

BACKGROUND

Stroke risk in atrial fibrillation is assessed by using the CHA₂DS₂-VASc score. Sex category (Sc, ie, female sex) confers 1 point on CHA₂DS₂-VASc. We hypothesized that female sex is a stroke risk modifier, rather than an overall risk factor, when added to a CHA₂DS₂-VA (sex-independent thromboembolism risk) score scale.

METHODS

Using 3 nationwide registries, we identified patients with incident nonvalvular atrial fibrillation from January 1, 1997, through December 31, 2015. Patients receiving oral anticoagulant treatment at baseline were excluded, and person-time was censored at the time of treatment initiation (if any). CHA₂DS₂-VA scores were calculated for men and women, and were followed for up to 1 year in the Danish National Patient Registry. The primary outcome was a primary hospital code for ischemic stroke or systemic embolism (thromboembolism). We calculated crude event rates for risk strata as events per 100 person-years. For quantifying absolute risk of stroke, we calculated risks based on the pseudovalue method. Female sex as a prognostic factor was investigated by inclusion as an interaction term on the CHA₂DS₂-VA score to calculate the thromboembolic risk ratio for different score points.

RESULTS

A total of 239 671 patients with atrial fibrillation (48.7% women) contributed to the analyses. The mean ages for women and men were 76.6 years and 70.3 years, respectively; the mean CHA₂DS₂-VA scores were 2.7 for women and 2.3 for men. The overall 1-year thromboembolic rate per 100 person-years for women was 7.3 and 5.7 for men. The 1-year absolute risk of thromboembolism was 0.5% among men and women with a CHA₂DS₂-VA score of 0 and increased up to >7% among very comorbid patients (score >5). The risk ratio (male as reference) across points >1 indicated that women exhibit a higher stroke risk. The interaction was statistically significant (P<0.001).

CONCLUSIONS

Female sex is a risk modifier for stroke in patients with atrial fibrillation. Initial decisions on oral anticoagulant treatment could be guided by a CHA₂DS₂-VA score (ie, excluding the sex category criterion), but the Sc risk component modifies and accentuates stroke risk in women who would have been eligible for oral anticoagulant treatment on the basis of ≥2 additional stroke risk factors.

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.

Antithrombotic treatment patterns in patients with atrial fibrillation in Italy pre- and post-DOACs: the REPAIR study

AIM

To evaluate antithrombotic treatment patterns in patients in Italy with nonvalvular atrial fibrillation (NVAF) before and after direct oral anticoagulants (DOACs) were approved.

METHODS

This analysis included patients with a discharge diagnosis of NVAF in 2010 and 2014, which constituted the pre- and post-DOACs populations, respectively.

RESULTS

Approximately 90% of patients were eligible for oral anticoagulant (OAC) therapy. Overall use of OACs increased from 38% in 2010 to 45% in 2014; use of antiplatelet therapy decreased from 36 to 25%. Approximately 14% of eligible patients remained untreated.

CONCLUSION

Although an improvement in OAC prescription was observed post-DOACs launch, treatment patterns in Italy suggest that a proportion of patients with NVAF are still undertreated or do not receive appropriate therapy.

A Propensity Score Matched Comparison of Clinical Outcomes in Atrial Fibrillation Patients Taking Vitamin K Antagonists: Comparing the "Real-World" vs Clinical Trials

OBJECTIVE

To investigate the incidence and risk of adverse clinical outcomes in a "real-world" cohort of patients with atrial fibrillation (AF) anticoagulated with vitamin K antagonists (VKAs) from the Murcia AF Project in comparison with the warfarin arm of the randomized clinical trial (RCT) AMADEUS (Evaluating the Use of SR34006 Compared to Warfarin or Acenocoumarol in Patients With Atrial Fibrillation).

PATIENTS AND METHODS

We included 1361 patients with AF from the Murcia AF Project (recruitment from May 1, 2007, to December 1, 2007) and 2293 from the AMADEUS trial (started in September 2003 and primary completed in March 2006), all taking VKA treatment. After propensity score matching (PSM), we investigated differences in rates and risks of several events, including major bleeding, ischemic stroke, and all-cause mortality at 365 (interquartile range, 275-428) days of follow-up.

RESULTS

After PSM there were 1324 patients for the comparative analysis, whereby annual event rates for most adverse events were significantly higher in the "real-world" population. Cox regression analyses demonstrated that the risk of primary outcomes was also increased in the "real-world" (vs RCT: hazard ratio [HR], 6.32; 95% CI, 2.84-14.03 for major bleeding; HR, 3.56, 95% CI, 1.22-10.42 for ischemic stroke; HR, 5.13, 95% CI, 3.02-8.69 for all-cause mortality). The risk of all other adverse events was higher in the real-world cohort, except for cardiovascular mortality.

CONCLUSION

This study comparing the Murcia AF Project and the AMADEUS trial demonstrates that there is a great heterogeneity in both populations, which is translated into a higher risk of several adverse outcomes in the real-world cohort, including major bleeding, ischemic stroke, and mortality.

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.

Atrial fibrillation in the Middle East: unmapped, underdiagnosed, undertreated

INTRODUCTION

Atrial fibrillation (AF) is the commonest persistent cardiac arrhythmia with an estimated incidence rate of between 1.5-2% and an important cause of strokes. Few epidemiological studies and clinical trials on the management of AF have been conducted outside Europe and North America. These gaps in our understanding of AF likely lead to sub-optimal management of patients with AF in the rest of the world. Areas covered: We discuss the epidemiology, treatment and clinical outcomes for AF in the Middle East after systematic review of published work for AF from the Middle East. We also discuss important clinical trials on AF conducted in the West in the same period to help contextualize our findings. Expert commentary: The few available Middle East studies suggest important epidemiological differences between Middle Eastern and Western AF populations. In particular, the Middle Eastern AF population is younger and have more co-morbidities than patients in the West. We find that significant numbers of moderate to high risk patients with AF are either undertreated or untreated placing them at increased risk of complications such as stroke. More studies in the Middle Eastern population are required to aid the development of region-specific clinical guidelines to improve patient care.