Association between Body Mass Index and Clinical Outcomes in Patients with Non-valvular Atrial Fibrillation Receiving Direct Oral Anticoagulants: A New Piece of Evidence on the Obesity Paradox from China

Fibrinaloid Microclots and Atrial Fibrillation

Atrial fibrillation (AF) is a comorbidity of a variety of other chronic, inflammatory diseases for which fibrinaloid microclots are a known accompaniment (and in some cases, a cause, with a mechanistic basis). Clots are, of course, a well-known consequence of atrial fibrillation. We here ask the question whether the fibrinaloid microclots seen in plasma or serum may in fact also be a cause of (or contributor to) the development of AF. We consider known 'risk factors' for AF, and in particular, exogenous stimuli such as infection and air pollution by particulates, both of which are known to cause AF. The external accompaniments of both bacterial (lipopolysaccharide and lipoteichoic acids) and viral (SARS-CoV-2 spike protein) infections are known to stimulate fibrinaloid microclots when added in vitro, and fibrinaloid microclots, as with other amyloid proteins, can be cytotoxic, both by inducing hypoxia/reperfusion and by other means. Strokes and thromboembolisms are also common consequences of AF. Consequently, taking a systems approach, we review the considerable evidence in detail, which leads us to suggest that it is likely that microclots may well have an aetiological role in the development of AF. This has significant mechanistic and therapeutic implications.

Comparison of the Efficacy and Safety of Rivaroxaban and Low Molecular Heparin in Preventing Venous Thromboembolism in Inpatient Cancer Patients

BACKGROUND

There are few studies on using rivaroxaban and low molecular heparin (LMWH) to prevent venous thromboembolism (VTE) in hospitalized cancer patients.

OBJECTIVE

We conducted a retrospective study to evaluate the efficacy and safety of rivaroxaban versus LMWH for the primary prevention of VTE in inpatient cancer patients.

METHODS

Information on patients was collected through 6-month follow-up and medical record inquiries. Clinical outcomes included VTE, total bleeding, thrombosis, major bleeding, minor bleeding, all-cause death, and a composite endpoint of bleeding, thrombosis, and death.

RESULTS

A total of 602 hospitalized cancer patients were included in this study. During 6 months of follow-up, there were 26 VTE events (8.6%), 42 total bleeding events (7.0%), 62 all-cause deaths (10.3%), and 140 composite endpoints (23.3%). After adjusting for various confounding factors, there were no significant differences between the rivaroxaban and LMWH for VTE events (OR = 0.851, 95% CI [0.387-1.872], P=0.688), total bleeding (OR = 1.690, 95% CI [0.768-3.719], P = 0.192], thrombosis events (OR = 0.919, 95% CI [0.520-1.624], P = 0.772], major bleeding (OR = 0.276, 95% CI [0.037-2.059], P = 0.209), all-cause death (OR = 0.994, 95% CI [0.492-2.009], P = 0.987), and composite endpoints (OR = 0.994, 95% CI [0.492-2.009], P = 0.987), while minor bleeding (OR = 3.661 95% CI [1.000-7.083], P = 0.050) was significantly higher in the rivaroxaban than in the LMWH.

CONCLUSIONS AND RELEVANCE

In thromboprophylaxis in inpatient cancer patients, rivaroxaban has a similar rate of VTE and bleeding events as LMWH. Our results may provide a reference for the clinical use of rivaroxaban to prevent VTE in hospitalized cancer patients.

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.

HACE1 expression in heart failure patients might promote mitochondrial oxidative stress and ferroptosis by targeting NRF2

BACKGROUND

Heart failure is a prevalent and life-threatening medical condition characterized by abnormal atrial electrical activity, contributing to a higher risk of ischemic stroke. Atrial remodelling, driven by oxidative stress and structural changes, plays a central role in heart failure progression. Recent studies suggest that HACE1, a regulatory gene, may be involved in cardiac protection against heart failure.

METHODS

Clinical data analysis involved heart failure patients, while an animal model utilized C57BL/6J mice. RT-PCR, microarray analysis, histological examination, ELISA, and Western blot assays were employed to assess gene and protein expression, oxidative stress, and cardiac function. Cell transfection and culture of mouse atrial fibroblasts were performed for in-vitro experiments.

RESULTS

HACE1 expression was reduced in heart failure patients and correlated negatively with collagen levels. In mouse models, HACE1 up-regulation reduced oxidative stress, mitigated fibrosis, and improved cardiac function. Conversely, HACE1 knockdown exacerbated oxidative stress, fibrosis, and cardiac dysfunction. HACE1 also protected against ferroptosis and mitochondrial damage. NRF2, a transcription factor implicated in oxidative stress, was identified as a target of HACE1, with HACE1 promoting NRF2 activity through ubiquitination.

CONCLUSIONS

HACE1 emerges as a potential therapeutic target and diagnostic marker for heart failure. It regulates oxidative stress, mitigates cardiac fibrosis, and protects against ferroptosis and mitochondrial damage. The study reveals that HACE1 achieves these effects, at least in part, through NRF2 activation via ubiquitination, offering insights into novel mechanisms for heart failure pathogenesis and potential interventions.

Safety and efficacy of direct oral anticoagulation in patients with and without radiofrequency ablation of non-valvular atrial fibrillation: a multicenter retrospective cohort study

BACKGROUND

Based on the few available studies on the prognostic benefit of using direct oral anticoagulants (DOACs) after atrial fibrillation (AF) ablation. Therefore, this study aimed to evaluate the prognostic differences between patients who underwent radiofrequency ablation (RFA) and those without RFA taking DOACs.

METHODS

This is a multicenter retrospective cohort study enrolling 6137 patients with non-valvular AF (NVAF) at 15 hospitals in China. Patient information was collected through a mean follow-up of 10 months and medical record queries. Clinical outcomes included major bleeding, total bleeding, thrombosis, all-cause death, and a composite endpoint of bleeding, thrombosis, and all-cause death.

RESULTS

After adjusting for confounders and propensity score matching (PSM), patients with RFA of NVAF had a significantly lower risk of major bleeding [OR 0.278 (95% CI, 0.150-0.515), P<0.001], thrombosis [OR 0.535 (95% CI, 0.316-0.908), P=0.020] and the composite endpoint [ OR 0.835 (95% CI, 0.710-0.982), P=0.029]. In the RFA PSM cohort, dabigatran was associated with reduced all-cause death in patients with RFA of NVAF [OR 0.420 (95% CI, 0.212-0.831), P=0.010]. In the no RFA PSM cohort, rivaroxaban was associated with a reduction in major bleeding [OR 0.521 (95% CI, 0.403-0.673), P<0.001], total bleeding [OR 0.114 (95% CI, 0.049-0.266), P<0.001], and the composite endpoint [OR 0.659 ( 95% CI, 0.535-0.811), P<0.001].

CONCLUSION

Among patients with NVAF treated with DOACs, RFA was a negative correlate of major bleeding, thrombosis, and composite endpoints but was not associated with total bleeding or all-cause mortality.

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.

Off-label dose direct oral anticoagulants and clinical outcomes in Asian patients with atrial fibrillation: A new evidence of Asian dose

AIM

This study aimed to evaluate the label compliance of DOACs in the Chinese AF population and explore the relationship between inappropriate DOACs dosage and clinical results.

METHODS AND RESULTS

This is a retrospective multicenter cohort study conducted in 14 centers in China. According to the China Food and Drug Administration(CFDA) label and the recommendations of international guidelines, we divided patients into on-label dosage and off-label dosage. We then compared the clinical results after propensity score matching. We collect demographic information through the hospital information system and obtain clinical events through follow-up of patients or their families. Clinical results include major, minor, total bleeding, thrombosis, and all-cause death. 4191 patients with non-valvular AF (NVAF) were included, and approximately 55.6% and 1.7% of AF patients received off-label underdose and off-label overdose of DOACs, respectively. Compared with the on-label dose, DOACs with off-label underdose were associated with a significantly reduced risk of major bleeding (P = 0.004, OR = 0.23,95% CI: 0.08-0.69) and all-cause death (P<0.001, OR = 0.49,95% CI: 0.33-0.73). However, there was no significant difference in thrombotic events (P = 0.865 OR = 1.06,95% CI: 0.54-2.07) and minor bleeding (P = 0.465, OR = 1.10,95% CI: 0.85-1.43) risk.

CONCLUSIONS

About 57.3% of Asian AF patients received an off-label dose of DOACs in daily practice. Off-label underdose DOACs were associated with significantly lower risks of major bleeding, all-cause death, and similar risks of minor bleeding, thrombotic events compared with on-label dose DOACs. Further prospective randomized trials are needed to determine the optimal dose of DOACs in Asian patients with AF at high bleeding risk.

The "obesity paradox" in patients with atrial fibrillation: Insights from the Gulf SAFE registry

BACKGROUND

The prognostic impact of obesity on patients with atrial fibrillation (AF) remains under-evaluated and controversial.

METHODS

Patients with AF from the Gulf Survey of Atrial Fibrillation Events (Gulf SAFE) registry were included, who were recruited from six countries in the Middle East Gulf region and followed for 12 months. A multivariable model was established to investigate the association of obesity with clinical outcomes, including stroke or systemic embolism (SE), bleeding, admission for heart failure (HF) or AF, all-cause mortality, and a composite outcome. Restricted cubic splines were depicted to illustrate the relationship between body mass index (BMI) and outcomes. Sensitivity analysis was also conducted.

RESULTS

A total of 1,804 patients with AF and recorded BMI entered the final analysis (mean age 56.2 ± 16.1 years, 47.0% female); 559 (31.0%) were obese (BMI over 30 kg/m2). In multivariable analysis, obesity was associated with reduced risks of stroke/systematic embolism [adjusted odds ratio (aOR) 0.40, 95% confidence interval (CI), 0.18-0.89], bleeding [aOR 0.44, 95%CI, 0.26-0.74], HF admission (aOR 0.61, 95%CI, 0.41-0.90) and the composite outcome (aOR 0.65, 95%CI, 0.50-0.84). As a continuous variable, higher BMI was associated with lower risks for stroke/SE, bleeding, HF admission, all-cause mortality, and the composite outcome as demonstrated by the accumulated incidence of events and restricted cubic splines. This "protective effect" of obesity was more prominent in some subgroups of patients.

CONCLUSION

Among patients with AF, obesity and higher BMI were associated with a more favorable prognosis in the Gulf SAFE registry. The underlying mechanisms for this obesity "paradox" merit further exploration.