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

Sex Differences in Perihematomal Edema Volume and Outcome After Intracerebral Hemorrhage

BACKGROUND

Although larger hematoma volume is associated with worse outcome after intracerebral hemorrhage (ICH), the association between perihematomal edema (PHE) volume and outcome remains uncertain, as does the impact of sex on PHE and outcome. Here we aimed to determine whether larger PHE volume is associated with worse outcome and whether PHE volume trajectories differ by sex.

METHODS

We conducted a post hoc analysis of the Factor VIIa for Acute Hemorrhagic Stroke Treatment (FAST) trial, which randomized patients with ICH to receive recombinant activated factor VIIa or placebo. Computerized planimetry calculated PHE and ICH volumes on serial computed tomography (CT) scans (at baseline [within 3 h of onset], at 24 h, and at 72 h). Generalized estimating equations examined interactions between sex, CT time points, and FAST treatment arm on PHE and ICH volumes. Mixed and multivariable logistic models examined associations between sex, PHE, and outcomes.

RESULTS

A total of 781 patients with supratentorial ICH (mean age 65 years) were included. Compared to women (n = 296), men (n = 485) had similar median ICH (14.9 vs. 13.6 mL, p = 0.053) and PHE volumes (11.1 vs. 10.5 mL, p = 0.56) at baseline but larger ICH and PHE volumes at 24 h (19.0 vs. 14.0 mL, p < 0.001; 22.2 vs. 15.7 mL, p < 0.001) and 72 h (16.0 vs. 11.8 mL, p < 0.001; 28.7 vs. 19.9 mL, p < 0.001). Men had higher absolute early PHE expansion (p < 0.001) and more hematoma expansion (growth ≥ 33% or 6 mL at 24 h, 33% vs. 22%, p < 0.001). An interaction between sex and CT time points on PHE volume (p < 0.001), but not on ICH volume, confirmed a steeper PHE trajectory in men. PHE expansion (per 5 mL, odds radio 1.19, 95% confidence interval 1.10-1.28), but not sex, was associated with poor outcome.

CONCLUSIONS

Early PHE expansion and trajectory in men were significantly higher. PHE expansion was associated with poor outcomes independent of sex. Mechanisms leading to sex differences in PHE trajectories merit further investigation.

Sex-specific comparative outcomes between oral anticoagulants in patients with atrial fibrillation: a systematic review and meta-analysis

AIMS

Women with atrial fibrillation (AF) are under-represented in randomised controlled trials (RCTs) of direct oral anticoagulants (DOACs). This systematic review and meta-analysis of RCTs and observational studies examined sex-specific outcomes of DOACs in AF.

METHODS

PubMed, Embase, Web of Science and Cochrane Library were searched from January 2008 to November 2022. Sex-specific comparative outcomes of stroke/systemic embolism (SE), major bleeding, intracranial haemorrhage (ICH) and gastrointestinal bleeding (GIB) between oral anticoagulants were pooled using random effects models. P values for interaction were calculated to examine differences in results between sexes. RCTs and observational studies were meta-analysed separately.

RESULTS

5 RCTs and 33 observational studies were included, totalling 1 085 931 women and 1 387 123 men. Meta-analyses showed that for both sexes, DOAC versus warfarin was generally associated with lower risk of stroke/SE, major bleeding and ICH; in DOAC-DOAC comparisons, rivaroxaban versus dabigatran had higher GIB risk. The only sex-specific difference observed was that when compared with warfarin, women had higher GIB risk with rivaroxaban (women: pooled risk ratio (pRR)=1.34, 95% CI=1.18 to 1.51; men: pRR=0.97, 95% CI=0.85 to 1.10; p value for interaction (p for interaction)<0.001) and possibly dabigatran (women: pRR=1.25, 95% CI=0.92 to 1.70; men: pRR=0.83, 95% CI=0.72 to 0.97; p-for-interaction=0.02). The sex difference in GIB remained for rivaroxaban when a Bonferroni-corrected significance level was used (α=0.003). No sex-specific GIB data for apixaban and edoxaban was available for the meta-analysis.

CONCLUSIONS

For both sexes, DOACs generally demonstrated favourable effectiveness and safety over warfarin. However, observational data suggested that women may have higher GIB risk with rivaroxaban and possibly dabigatran than warfarin. Further studies are warranted to verify our findings and elucidate sex-specific GIB risk with apixaban and edoxaban, of which the data is currently lacking.

PROSPERO REGISTRATION NUMBER

CRD42022325027.

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.

Sex differences in perihematomal edema volume and outcome after intracerebral hemorrhage

Objective

To determine whether in patients with intracerebral hemorrhage (ICH) perihematomal edema (PHE) volume trajectories differ by sex.

Methods

We conducted a post-hoc analysis of the Factor-VII-for-Acute-Hemorrhagic-Stroke-Treatment (FAST) trial that randomized patients with ICH to receive recombinant activated Factor VIIa or placebo. Computerized planimetry calculated PHE and ICH volumes on serial CT scans (at baseline [within 3 hours of onset], at 24, and at 72 hours). Generalized estimating equations examined interactions between sex, CT-timepoints, and FAST treatment-arm on PHE and ICH volumes. Mixed and multivariate logistic models examined associations between sex, PHE, and outcomes.

Results

781 with supratentorial ICH (mean age 65 years) were included. Compared to women (n=296), men (n=485) had similar median ICH (14.9 versus 13.6 ml, p=0.053), and PHE volumes (11.1 versus 10.5 ml, p=0.56) at baseline but larger ICH and PHE at 24 hours (19.0 versus 14.0, p<0.001; 22.2 versus 15.7, p<0.001) and 72 hours (16.0 versus 11.8, p<0.001; 28.7 versus 19.9, p<0.001). Men had higher absolute PHE expansion (p<0.001), and more hematoma expansion (growth ≥33% or 6 mL at 24 hours, 33% versus 22%, p<0.001). An interaction between sex and CT-timepoints on PHE (p<0.001) but not on ICH volumes confirmed a steeper PHE trajectory in men. PHE expansion (per 5mL, odds radio, 1.19, 95%-confidence interval 1.10-1.28), but not sex, was associated with poor outcome.

Conclusions

PHE expansion and trajectory in men were significantly higher. PHE expansion was associated with poor outcomes independent of sex. Mechanisms leading to sex differences in PHE trajectories merit further investigation.

What is already known on this topic

Prior research has reported sex differences in intracerebral hemorrhage (ICH) characteristics and some studies suggest worse outcome after ICH in women. However, we do not have a good understanding whether there are sex differences in perihematomal edema (PHE) volume trajectories, or whether sex, independent of confounders, is associated with poor after ICH.

What this study adds

In this post-hoc analysis of 781 patients with supratentorial ICH from the Factor-VII-for-Acute-Hemorrhagic-Stroke-Treatment (FAST) trial in which patients underwent brain CT imaging time-locked to symptom onset (within 3 hours of symptom onset, at 24 hours, and at 72 hours), men compared to women had similar ICH and PHE volumes at baseline, but larger ICH expansion and PHE expansion on follow up imaging. The PHE but not the ICH volume trajectory across scans was significantly higher in men than in women. While PHE expansion was associated with poor outcome at 90 days, outcome between the sexes was similar at 90 days, and sex was not associated with outcome.

How this study might affect research practice or policy

The finding of heightened early PHE and ICH expansion in men may inform study design, patient recruitment strategies, and pre-specification of subgroup analyses in future interventional trials. The findings of this study also suggest that focusing on sex-specific factors may allow novel mechanistic insight into PHE, a major cause of secondary injury and poor outcome after ICH.

Sex differences in the inflammatory response to stroke

Ischemic stroke is a leading cause of morbidity and mortality and disproportionally affects women, in part due to their higher longevity. Older women have poorer outcomes after stroke with high rates of cognitive deficits, depression, and reduced quality of life. Post-stroke inflammatory responses are also sexually dimorphic and drive differences in infarct size and recovery. Factors that influence sex-specific immune responses can be both intrinsic and extrinsic. Differences in gonadal hormone exposure, sex chromosome compliment, and environmental/social factors can drive changes in transcriptional and metabolic profiles. In addition, how these variables interact, changes across the lifespan. After the onset of ischemic injury, necrosis and apoptosis occur, which activate microglia and other glial cells within the central nervous system, promoting the release of cytokines and chemokines and neuroinflammation. Cells involved in innate and adaptive immune responses also have dual functions after stroke as they can enhance inflammation acutely, but also contribute to suppression of the inflammatory cascade and later repair. In this review, we provide an overview of the current literature on sex-specific inflammatory responses to ischemic stroke. Understanding these differences is critical to identifying therapeutic options for both men and women.

Trends in oral anticoagulant use in patients with atrial fibrillation in Belgium from 2013 to 2019: A nationwide cohort study

AIM

Non-vitamin K antagonist oral anticoagulants (NOACs) are increasingly preferred over vitamin K antagonists (VKAs) in atrial fibrillation (AF) management. However, differences in oral anticoagulant (OAC) prescribing according to patient's age, sex and physician's specialty may be present. Therefore, incident and prevalent use of OACs, NOACs and VKAs, stratified by age, sex and prescriber, and factors associated with the choice of OAC were investigated.

METHODS

Using two Belgian nationwide healthcare databases, AF patients ≥45 years old with ≥1 OAC prescription claim between 2013 and 2019 were identified. OAC use was investigated per half-year. Factors influencing NOAC vs. VKA initiation were identified by multivariable logistic regression.

RESULTS

Among 448 661 included OAC-treated AF patients, 297 818 were newly treated. Incident OAC use ranged from 45-49 to 42-44 users/10 000 persons between 2013 and 2019, whereas prevalent OAC use increased from 337 to 435 users/10 000 persons. Incident and prevalent NOAC use exceeded VKA use since 2013 and 2015, respectively, and NOACs represented 92% of incident and 81% of prevalent OAC users in 2019. Apixaban was the most frequently used NOAC since 2016. NOACs were significantly more prescribed by cardiologists and to older patients, whereas VKAs were more initiated in patients with cardiovascular, renal and hepatic comorbidities. Prevalent OAC use increased less in women than men (25.3% vs. 33.0% between 2013 and 2019) and female subjects had 5% significantly lower odds of NOAC vs. VKA initiation than men.

CONCLUSION

Since 2013, prevalent anticoagulant use increased almost one third in Belgium, while incident use was stable. Potential (N)OAC underuse in women requires further exploration.

Safety and Efficacy Re-Evaluation of Edoxaban and Rivaroxaban Dosing With Plasma Concentration Monitoring in Non-Valvular Atrial Fibrillation: With Observations of On-Label and Off-Label Dosing

Background: Off-label dosing of direct oral anticoagulants (DOAC) as a treatment for non-valvular atrial fibrillation (NVAF) is problematic. Here, we investigated the status of rivaroxaban and edoxaban dosing by monitoring plasma concentrations (PCs). Methods and Results: We monitored drug PCs in 391 and 333 outpatients receiving rivaroxaban and edoxaban, respectively, for NVAF. Drug doses were adjusted if the PC was above the cut-off value (rivaroxaban: 404 ng/mL; edoxaban: 402 ng/mL), determined from receiver operating characteristic curves for predicting bleeding events. On-label standard dosing was reduced to off-label underdosing due to high PCs above the cut-off more often for rivaroxaban (28.1%) than edoxaban (12.6%; P<0.001). Over a median follow-up of 13 months for rivaroxaban and 10 months for edoxaban, the annual incidence of bleeding events was higher with rivaroxaban than with edoxaban (4.88 vs. 3.73 patient-years; P<0.05), although no thromboembolic events occurred in either group. Furthermore, for patients with creatinine clearance >50 mL/min and body weight ≤60 kg, there was a greater incidence of bleeding events with rivaroxaban on-label 15 mg dosing than with edoxaban on-label 30 mg dosing (22.2% vs 2.9%; P<0.01). Conclusions: Monitoring the PCs of rivaroxaban and edoxaban in NVAF patients enables dose adjustments to reduce bleeding risk. The incidence of bleeding under drug PC monitoring was less in the edoxaban than rivaroxaban group.

Sex Differences Among Patients Receiving Edoxaban vs Vitamin K Antagonist for Atrial Fibrillation After TAVR

Background

In the ENVISAGE-TAVI AF (Edoxaban vs Standard of Care and Their Effects on Clinical Outcomes in Patients Having Undergone Transcatheter Aortic Valve Implantation-Atrial Fibrillation) trial, edoxaban was noninferior to vitamin K antagonists (VKA) for a composite outcome of ischemic and bleeding complications but increased major bleeding in patients with atrial fibrillation after successful transcatheter aortic valve replacement. Women are at higher risk of bleeding and stroke than men after transcatheter aortic valve replacement. It is unclear whether the effect of edoxaban on these complications varies in relation to sex.

Objectives

This study was to assess the effect of edoxaban vs VKA according to sex in the ENVISAGE-TAVI AF trial.

Methods

The primary outcomes were net adverse cardiovascular events (NACE) and major bleeding, assessed considering the effective time on study medication (safety analysis).

Results

Out of 1,377 patients, 658 (47.8%) were women. Risks for ischemic and major bleeding outcomes were similar between women and men. Edoxaban compared to VKA was associated with a similar risk of NACE in women (HR: 1.16; 95% CI: 0.81-1.65) and men (HR: 1.08; 95% CI: 0.76-1.53; P for interaction = 0.820) and a higher risk of major bleeding in both sexes (P for interaction = 0.170). The risk increase of major bleeding was attenuated in women (HR: 1.11; 95% CI: 0.69-1.79) as compared to men (HR: 1.75; 95% CI: 1.07-2.85). There were no treatment-related differences for ischemic complications in both sexes.

Conclusions

Edoxaban compared to VKA was associated with a similar risk of NACE and higher risk of major bleeding in both sexes. The increase in bleeding complications with edoxaban was attenuated in women.

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.

Edoxaban versus Warfarin in high-risk patients with atrial fibrillation: A comprehensive analysis of high-risk subgroups

BACKGROUND

To compare the efficacy and safety of edoxaban vs warfarin in high-risk subgroups.

METHODS

ENGAGE AF-TIMI 48 was a multicenter randomized, double-blind, controlled trial in 21,105 patients with atrial fibrillation (AF) within 12 months and CHADS₂ score >2 randomized to higher-dose edoxaban regimen (HDER) 60 mg/reduced 30 mg, lower-dose edoxaban regimen (LDER) 30 mg/reduced 15 mg, or warfarin, and followed for 2.8 years (median). The primary outcome for this analysis was the net clinical outcome (NCO), a composite of stroke/systemic embolism events, major bleeding, or death. Multivariable risk-stratification analysis was used to categorize patients by the number of high-risk features.

RESULTS

The annualized NCO rates in the warfarin arm were highest in patients with malignancy (19.2%), increased fall risk (14.0%), and very-low body weight (13.5%). The NCO rates increased with the numbers of high-risk factors in the warfarin arm: 4.5%, 7.2%, 9.9% and 14.6% in patients with 0 to 1, 2, 3, and >4 risk factors, respectively (P_trend <0.001). Versus warfarin, HDER was associated with significant reductions of NCO in most of the subgroups: elderly, patients with moderate renal dysfunction, prior stroke/TIA, of Asian race, very-low body weight, concomitant single antiplatelet therapy, and VKA-naïve. With more high-risk features (0->4+), the absolute risk reductions favoring edoxaban over warfarin increased: 0.3%->2.0% for HDER; 0.4%->3.4% for LDER vs warfarin (P = .065 and P < .001, respectively).

CONCLUSIONS

While underuse of anticoagulation in high-risk patients with AF remains common, substitution of effective and safer alternatives to warfarin, such as edoxaban, represents an opportunity to improve clinical outcomes.