Direct-Acting Oral Anticoagulant Choice for Stroke Prevention in Obese Patients With Atrial Fibrillation

Direct oral anticoagulants and the risk of adverse clinical outcomes among patients with different body weight categories: a large hospital-based study

OBJECTIVE

Through predictable pharmacokinetics-including a convenient fixed-dose regimen, direct oral anticoagulants (DOACs) are preferred over previous treatments in anticoagulation for various indications. However, the association between higher body weight and the risk of adverse consequences is not well studied among DOAC users. We aim to explore the association of body weight and adverse clinical outcomes in DOAC users.

METHODS

A total of 97,413 anonymised DOAC users in a tertiary care setting were identified following structured queries on the electronic health records (EHRs) to extract the feature-rich anonymised dataset. The prepared dataset was analysed, and the features identified with machine learning (ML) informed the adjustments of covariates in the multivariate regression analysis to examine the association. Kaplan-Meier analysis was performed to evaluate the mortality benefits of DOACs.

RESULTS

Among DOAC users, the odds of adverse clinical outcomes, such as clinically relevant non-major bleeding (CRNMB), ischaemic stroke, all-cause mortality, and prolonged hospital stay, were lower in patients with overweight, obesity, or morbid obesity than in patients with normal body weight. The odds of ischaemic stroke (OR 0.42, 95% CI: 0.36-0.88, p = 0.001) and all-cause mortality (OR 0.87, 95% CI: 0.81-0.95, p = 0.001) were lower in patients with morbid obesity than in patients with normal body weight. In the Kaplan-Meier analysis, apixaban was associated with a significantly lower rate of mortality overall and in obesity and overweight subgroups than other DOACs (p < 0.001). However, rivaroxaban performed better than apixaban in the morbid obesity subgroup (p < 0.001).

CONCLUSION

This study shows the positive effects of DOAC therapy on clinical outcomes, particularly in patients with high body weight. However, this still needs validation by further studies particularly among patients with morbid obesity.

A Real-World Comparison of Apixaban and Rivaroxaban in Obese and Morbidly Obese Patients With Nonvalvular Atrial Fibrillation

Background: Contemporary guidelines for managing nonvalvular atrial fibrillation (NVAF) include apixaban and rivaroxaban as first-line anticoagulation treatment options. Minimal guidance is available regarding selecting anticoagulants for patients with class I-III obesity. Objective: This study aims to evaluate the comparative effectiveness and safety of apixaban and rivaroxaban in both obese and morbidly obese patients with NVAF. Methods: A retrospective cohort study was conducted at an outpatient cardiovascular clinic after Institutional Review Board approval. Patients were eligible if they were ≥18 years of age, had a BMI ≥30 kg/m2, and took apixaban or rivaroxaban for NVAF for ≥3 months. The primary endpoint was the composite rate of stroke, transient ischemic attack (TIA), myocardial infarction (MI), or presence of atrial thrombosis. Bleeding events were evaluated as the primary safety endpoint. Results: Combined, the cohorts consisted of 303 obese or morbidly obese patients. The primary composite endpoint occurred in 3.8% of patients taking apixaban and 1.7% of patients taking rivaroxaban (P = .28). Both clinically relevant, non-major and major bleeding occurred more often in the apixaban arm, but this difference was not statistically significant; however, bleeding risk may have been skewed due to differences in baseline characteristics. Conclusion and Relevance: For obese and morbidly obese patients prescribed either apixaban or rivaroxaban for NVAF, rates of stroke, TIA, MI, and atrial thrombosis did not differ. The preferred DOAC for patients with class I-III obesity remains elusive, but current data points to a patient-centered approach for anticoagulant selection.

Management of Patients Treated with Direct Oral Anticoagulants in Clinical Practice and Challenging Scenarios

It is well established that direct oral anticoagulants (DOACs) are the cornerstone of anticoagulant strategy in atrial fibrillation (AF) and venous thromboembolism (VTE) and should be preferred over vitamin K antagonists (VKAs) since they are superior or non-inferior to VKAs in reducing thromboembolic risk and are associated with a lower risk of intracranial hemorrhage (IH). In addition, many factors, such as fewer pharmacokinetic interactions and less need for monitoring, contribute to the favor of this therapeutic strategy. Although DOACs represent a more suitable option, several issues should be considered in clinical practice, including drug-drug interactions (DDIs), switching to other antithrombotic therapies, preprocedural and postprocedural periods, and the use in patients with chronic renal and liver failure and in those with cancer. Furthermore, adherence to DOACs appears to remain suboptimal. This narrative review aims to provide a practical guide for DOAC prescription and address challenging scenarios.

A Real-World Exploration into Clinical Outcomes of Direct Oral Anticoagulant Dosing Regimens in Morbidly Obese Patients Using Data-Driven Approaches

INTRODUCTION

The clinical outcomes of direct oral anticoagulant (DOAC) dosage regimens in morbid obesity are uncertain due to limited clinical evidence. This study seeks to bridge this evidence gap by identifying the factors associated with clinical outcomes following the dosing of DOACs in morbidly obese patients.

METHOD

A data-driven observational study was carried out using supervised machine learning (ML) models with a dataset extracted from electronic health records and preprocessed. Following 70%:30% partitioning of the overall dataset via stratified sampling, the selected ML classifiers (e.g., random forest, decision trees, bootstrap aggregation) were applied to the training dataset (70%). The outcomes of the models were evaluated against the test dataset (30%). Multivariate regression analysis explored the association between DOAC regimens and clinical outcomes.

RESULTS

A sample of 4,275 morbidly obese patients was extracted and analysed. The decision trees, random forest, and bootstrap aggregation classifiers achieved acceptable (excellent) values of precision, recall, and F1 scores in terms of their contribution to clinical outcomes. The length of stay, treatment days, and age were ranked highest for relevance to mortality and stroke. Among DOAC regimens, apixaban 2.5 mg twice daily ranked highest for its association with mortality, increasing the mortality risk by 43% (odds ratio [OR] 1.430, 95% confidence interval [CI] 1.181-1.732, p = 0.001). On the other hand, apixaban 5 mg twice daily reduced the odds of mortality by 25% (OR 0.751, 95% CI 0.632-0.905, p = 0.003) but increased the odds of stroke events. No clinically relevant non-major bleeding events occurred in this group.

CONCLUSION

Data-driven approaches can identify key factors associated with clinical outcomes following the dosing of DOACs in morbidly obese patients. This will help design further studies to explore well tolerated and effective DOAC doses for morbidly obese patients.

Epicardial fat and atrial fibrillation: the perils of atrial failure

Obesity is a heterogeneous condition, characterized by different phenotypes and for which the classical assessment with body mass index may underestimate the real impact on cardiovascular (CV) disease burden. An epidemiological link between obesity and atrial fibrillation (AF) has been clearly demonstrated and becomes even more tight when ectopic (i.e. epicardial) fat deposition is considered. Due to anatomical and functional features, a tight paracrine cross-talk exists between epicardial adipose tissue (EAT) and myocardium, including the left atrium (LA). Alongside-and even without-mechanical atrial stretch, the dysfunctional EAT may determine a pro-inflammatory environment in the surrounding myocardial tissue. This evidence has provided a new intriguing pathophysiological link with AF, which in turn is no longer considered a single entity but rather the final stage of atrial remodelling. This maladaptive process would indeed include structural, electric, and autonomic derangement that ultimately leads to overt disease. Here, we update how dysfunctional EAT would orchestrate LA remodelling. Maladaptive changes sustained by dysfunctional EAT are driven by a pro-inflammatory and pro-fibrotic secretome that alters the sinoatrial microenvironment. Structural (e.g. fibro-fatty infiltration) and cellular (e.g. mitochondrial uncoupling, sarcoplasmic reticulum fragmentation, and cellular protein quantity/localization) changes then determine an electrophysiological remodelling that also involves the autonomic nervous system. Finally, we summarize how EAT dysfunction may fit with the standard guidelines for AF. Lastly, we focus on the potential benefit of weight loss and different classes of CV drugs on EAT dysfunction, LA remodelling, and ultimately AF onset and recurrence.

Effectiveness and Safety of Dabigatran in Atrial Fibrillation Patients with Severe Obesity: a Real-World Retrospective Cohort Study

BACKGROUND

Direct oral anticoagulants such as dabigatran are the preferred anticoagulant in treating atrial fibrillation (AF) patients due to their effectiveness and safety. Whether this applies to severely obese patients needs to be determined.

OBJECTIVE

To compare the effectiveness and safety of dabigatran with warfarin among AF patients with severe obesity.

DESIGN

Retrospective cohort study.

PARTICIPANTS

AF patients with a BMI >40kg/m2 or a weight >120kg receiving dabigatran or warfarin between 10/01/2010 and 12/31/2019 in a large integrated health system and followed through 08/01/2020.

INTERVENTIONS

Not applicable.

MAIN MEASURES

Primary effectiveness outcome was composite thromboembolism including transient ischemic attack, ischemic stroke, or systemic embolism. Primary safety outcome was composite bleeding including gastrointestinal bleeding, intracranial bleeding, or other bleeding. Secondary outcomes included the individual outcomes and all-cause mortality. Propensity score matching (PSM) was performed to create a 1:1 matched cohort and Cox proportional hazards model was used to estimate the hazard ratio (HR) of each outcome for dabigatran users compared to warfarin users.

KEY RESULTS

A total of 6848 patients receiving either dabigatran or warfarin were identified. In a 1:1 matched cohort, dabigatran users had a HR of 0.71 (95% confidence interval (CI): 0.56-0.91) for composite thromboembolism, a HR of 1.24 (95%CI: 1.07-1.42) for composite bleeding, and a HR of 0.57 (95% CI: 0.45-0.71) for all-cause mortality when compared to warfarin users.

CONCLUSIONS

Among AF patients with a BMI >40kg/m2 or a weight >120kg in a real-world clinical setting, dabigatran was effective in reducing the risk of thromboembolism and mortality but was associated with an increased risk of bleeding when compared to warfarin. Dabigatran may be a reasonable option for AF patients with severe obesity.

Expert Recommendations on the Usage of Non-vitamin K Antagonist Oral Anticoagulants (NOACs) from India: Current Perspective and Future Direction

Non-vitamin K antagonist oral anticoagulants (NOACs) are a new class of anticoagulant drugs used in the prevention and treatment of venous thromboembolism (VTE) and atrial fibrillation (AF). Anticoagulation requires the integration of the correct type and dose of oral anticoagulants based on patient characteristic, and therefore therapy needs to be individualized for each patient. Growing scientific evidence from studies on NOACs has led to a better understanding of their benefits and safety. A large amount of available data creates a necessity for an adaptable practical document for the usage of NOACs in India. The current consensus, developed by experts from India, aims to give recommendations on various frequently raised clinical questions with regards to NOACs and its usage. This practical document provides a platform upon which future guidelines, policies, training, and education for the use of NOACs can be tailored.

Comparative Effectiveness and Safety of DOAC Versus Warfarin among Obese Patients with Atrial Fibrillation

Background

Obese patients are underrepresented in clinical trials assessing the comparative effectiveness and safety of use of direct oral anticoagulants vs use in atrial fibrillation (AF) patients.

Methods

Using data from Quebec provincial administrative databases, for the years2010-2017, we created a retrospective cohort of patients with inpatient or outpatient coding for AF and obesity who were newly prescribed an oral anticoagulant. The primary safety outcome was a composite of intracranial, gastrointestinal, and major bleeding from other sites, and the primary effectiveness outcome was a composite of ischemic stroke, systemic embolism, acute myocardial infarction, and death in the first year after oral anticoagulant initiation. Treatment groups were compared using inverse-probability-of-treatment-weighting Cox proportional-hazards models.

Results

A total of 2263 patients were included, of whom 1253, 403, and 539 filled a warfarin, standard-dose rivaroxaban, and standard-dose apixaban prescription, respectively. Standard-dose rivaroxaban was associated with a similar composite safety (hazard ratio [HR] 0.91; 95% confidence interval [CI] 0.44-1.91) and composite effectiveness risk (HR 1.42; 95% CI 0.99-2.04) compared to warfarin, whereas standard-dose apixaban was associated with a lower composite safety (HR 0.40; 95% CI 0.16-0.98) and similar composite effectiveness risk (HR 0.96; 95% CI 0.67-1.39).

Conclusion

Use of direct oral anticoagulants in obese AF patients was associated with a similar effectiveness and safety profile to that of warfarin use.