Rivaroxaban Plus Aspirin in Obese and Overweight Patients With Vascular Disease in the COMPASS Trial

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.

EvidenceMap: a three-level knowledge representation for medical evidence computation and comprehension

OBJECTIVE

To develop a computable representation for medical evidence and to contribute a gold standard dataset of annotated randomized controlled trial (RCT) abstracts, along with a natural language processing (NLP) pipeline for transforming free-text RCT evidence in PubMed into the structured representation.

MATERIALS AND METHODS

Our representation, EvidenceMap, consists of 3 levels of abstraction: Medical Evidence Entity, Proposition and Map, to represent the hierarchical structure of medical evidence composition. Randomly selected RCT abstracts were annotated following EvidenceMap based on the consensus of 2 independent annotators to train an NLP pipeline. Via a user study, we measured how the EvidenceMap improved evidence comprehension and analyzed its representative capacity by comparing the evidence annotation with EvidenceMap representation and without following any specific guidelines.

RESULTS

Two corpora including 229 disease-agnostic and 80 COVID-19 RCT abstracts were annotated, yielding 12 725 entities and 1602 propositions. EvidenceMap saves users 51.9% of the time compared to reading raw-text abstracts. Most evidence elements identified during the freeform annotation were successfully represented by EvidenceMap, and users gave the enrollment, study design, and study Results sections mean 5-scale Likert ratings of 4.85, 4.70, and 4.20, respectively. The end-to-end evaluations of the pipeline show that the evidence proposition formulation achieves F1 scores of 0.84 and 0.86 in the adjusted random index score.

CONCLUSIONS

EvidenceMap extends the participant, intervention, comparator, and outcome framework into 3 levels of abstraction for transforming free-text evidence from the clinical literature into a computable structure. It can be used as an interoperable format for better evidence retrieval and synthesis and an interpretable representation to efficiently comprehend RCT findings.

Low dose rivaroxaban for the management of atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular disease is characterized by some risk of major adverse events despite the availability of effective medical therapies for secondary prevention. There is emerging evidence suggesting that thrombin partly contributes to this residual risk. In fact, thrombin (i.e., activated coagulation factor II) triggers not only the conversion of fibrinogen to fibrin but also platelet activation and various pathways responsible for pro-atherogenic and/or pro-inflammatory effects through interaction with protease activated receptors. To reduce the risk associated with thrombin activation, oral anticoagulants antagonists of vitamin K showed promise, but were associated with unacceptable bleeding rates. Direct oral anticoagulants targeting the activated factors X and II carry a lower risk of bleeding than vitamin K antagonists. Rivaroxaban, a direct inhibitor of activated factor X approved at the dose of 20 mg once daily for the prevention of thromboembolic events, has been also investigated at a reduced dose of 2.5 mg twice daily in several alternative scenarios of atherosclerotic cardiovascular disease, in combination with standard of care. Current guidelines recommend that low-dose rivaroxaban is given in an adjunct to standard therapy to patients with stable atherosclerosis and acute coronary syndromes at low bleeding risk. Several studies are underway to evaluate its putative benefits in other clinical settings.

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.

Anticoagulation and BMI: effect of high body weight on the safety and efficacy of direct oral anticoagulants

Obesity is an epidemic with rising prevalence, and obese patients are predisposed to comorbid conditions that increase risk for thromboembolic events. It is critical to identify safe and effective anticoagulation therapy for use in this population. Direct oral anticoagulants (DOACs) are a preferred option for anticoagulation in patients of normal weight due to many benefits and equivalent safety and efficacy to their vitamin K antagonist counterparts. However, the safety and efficacy of DOACs in obese patients is not well understood. This review describes recent studies on the pharmacokinetics, safety and efficacy, and clinical outcomes of the DOACs apixaban, rivaroxaban, edoxaban and dabigatran in obese patient populations. DOACs may be a beneficial alternative to vitamin K antagonist therapy in obese patient populations.

Direct Oral Anticoagulants Combined with Antiplatelet Therapy in the Treatment of Coronary Heart Disease: An Updated Meta-analysis

BACKGROUND

Direct oral anticoagulants (DOACs) combined with antiplatelet therapy for acute coronary syndrome (ACS) may reduce ischemic events, but there is no consensus on bleeding risk. Moreover, the effect of DOACs on stable coronary artery disease (CAD) needs to be elucidated. We conducted a meta-analysis to summarize the efficacy and safety of DOACs combined with antiplatelet therapy in the treatment of stable CAD and ACS.

METHODS

We searched PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials, then performed a systematic review of all 17 randomized controlled trials.

RESULTS

For patients with stable CAD, DOACs combined with antiplatelet therapy significantly reduced the rate of major adverse cardiovascular events (MACE) (risk ratio; 95% confidence interval: 0.88; 0.81-0.95) and ischemic stroke (0.62; 0.50-0.77), with a relatively low risk of major bleeding (1.72; 1.42-2.07). For patients with ACS, the combination of DOACs reduced the risk of MACE (0.91; 0.85-0.97), myocardial infarction (MI) (0.90; 0.83-0.98), and ischemic stroke (0.75; 0.58-0.97), accompanied by increased non-fatal bleeding events and intracranial hemorrhage (3.42; 1.76-6.65). Results were similar when restricting the analysis to phase III studies except for the rate of stroke in patients with ACS.

CONCLUSIONS

Combination therapy reduced the incidence of MI in ACS patients, but the risk of bleeding from intracranial hemorrhaging outweighs the benefit of MACE driven by MI. That is due to combination therapy having no positive impact on mortality; thus, the benefit-risk balance may be more favorable  in patients with stable CAD.