Anticoagulation Treatment and Outcomes of Venous Thromboembolism by Weight and Body Mass Index: Insights From the Veterans Health Administration

Efficacy and Safety of Direct Oral Anticoagulants versus Warfarin in Obese Patients (BMI ≥ 30 kg/m2) with Atrial Fibrillation or Venous Thromboembolism: An Updated Systematic Review and Meta-Analysis

Background: Real-world data show limited utilization of direct oral anticoagulants (DOACs) in obese patients (body mass index [BMI] ≥ 30 kg/m2) due to concerns regarding their efficacy and safety in this demographic. Aim: This review aimed to consolidate current evidence on the efficacy and safety of DOACs versus warfarin in obese patients with non-valvular atrial fibrillation (AF) or venous thromboembolism (VTE). The primary efficacy outcome assessed a composite of all-cause mortality, stroke, systemic embolism (SE), and myocardial infarction (MI). Methods: A systematic search was conducted in MEDLINE, SCOPUS, and Cochrane databases from inception to December 28, 2023. Data were synthesized using random-effects meta-analysis. Results: A total of 35 studies involving 434,320 participants were analyzed. DOAC use was associated with a significant reduction in the risk of the composite outcome (RR = 0.80, 95% CI [0.65, 0.98], I2 = 95%), hemorrhagic stroke (RR = 0.58, 95% CI [0.38, 0.88], I2 = 92%), major bleeding (RR = 0.76, 95% CI [0.63, 0.92], I2 = 94%), gastrointestinal bleeding (RR = 0.59, 95% CI [0.49, 0.72], I2 = 88%), and intracranial bleeding (RR = 0.45, 95% CI [0.34, 0.60], I2 = 44%) compared to warfarin. A non-significant benefit of DOACs was observed for all-cause mortality, MI, the composite of stroke or SE, ischemic stroke, SE, VTE, and minor bleeding compared to warfarin. Subgroup analysis indicated no significant effect modification based on the indication for anticoagulation or study design. Conclusions: DOACs demonstrated a favorable efficacy and safety profile in obese individuals compared to warfarin.

European expert consensus recommendations on the primary care use of direct oral anticoagulants in patients with venous thromboembolism

BACKGROUND

Direct oral anticoagulants for the treatment of venous thromboembolism are supported by robust clinical trial evidence. Despite published guidance, general practitioners are faced with increasingly complex decisions and implementation remains sub-optimal in certain real-world scenarios.

METHODS

A two stage formal consensus exercise was performed to formulate consensus statements and a summary guide, facilitating optimal management of direct oral anticoagulants in venous thromboembolism patients by generalist physicians across Europe. An online questionnaire distributed to a broad panel (Phase 1), followed by a virtual panel discussion by an expert group (Phase 2) were conducted. Phase 1 statements covered nine management domains, and were developed via a literature review and expert steering committee. Participants rated statements by their level of agreement. Phase 1 responses were collated and analysed prior to discussion and iterative refinement in Phase 2.

RESULTS

In total 56 participants from across Europe responded to Phase 1. The majority had experience working as general practitioners. Consensus indicated that direct oral anticoagulants are the treatment of choice for managing patients with venous thromboembolism, at initiation and for extended treatment, with a review at three to six months to re-assess treatment effect and risk profile. Direct oral anticoagulant choice should be based on individual patient factors and include shared treatment choice between clinicians and patients; the only sub-group of patients requiring specific guidance are those with cancer.

CONCLUSION

Results demonstrate an appreciation of best practices, but highlight challenges in clinical practice. The patient pathway and consensus recommendations provided, aim to highlight key considerations for general practice decision making, and aid optimal venous thromboembolism treatment.

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.

International Normalized Ratio Predicts Recurrence and Bleeding in Patients With Acute Venous Thromboembolism Who Undergo Direct Oral Anticoagulants

Prothrombin time/international normalized ratio (PT/INR) is related to both antithrombotic effect and risk of bleeding. Its role in the prediction of venous thromboembolism (VTE) recurrence and bleeding for patients with acute VTE who undergo direct oral anticoagulants (DOACs) treatment is unclear, despite previous studies revealed some association between them. The predictive efficiency of INR for VTE recurrence and bleeding were analyzed in a retrospective cohort with VTE patients who underwent DOACs treatment. Then its predictive efficiency for VTE recurrence and bleeding were validated in a prospective cohort with the acquired cutoffs range, and compared with anti-Xa level, DASH and VTE-BLEED scores. In the retrospective cohort (n = 1083), the sensitivity and specificity of INR for the prediction of VTE recurrence were 79.4% and 92.8%, respectively. The area under the curve (AUC) was 0.881 (0.803-0.960)(P = .025). The cutoff value of INR was 0.9. The sensitivity and specificity of INR for the prediction of bleeding were 85.7% and 77.9%, respectively. The AUC was 0.876 (0.786-0.967)(P < .001). The cutoff value of INR was 2.1. In the prospective cohort (n = 202), the calibration showed that there were 4 (50%) patients with VTE recurrence, 156 (97.5%) patients with non-recurrence and bleeding (non-R&B), and 20 (58.8%) patients with bleeding in the low (INR < 0.9)(n = 8), intermediate (0.9 ≤ INR ≤ 2.1)(n = 160), and high (INR > 2.1)(n = 34) groups, respectively. The baseline PT/INR value at the initiation of DOACs treatment is an independent predictor for VTE recurrence and bleeding in patients with acute VTE who undergo DOACs treatment.

Real life results of direct-acting oral anticoagulants recommended-dose in obese vs normal-weight patients with venous thromboembolism

BACKGROUND

There is scarce evidence on the effectiveness and safety of recommended-dose direct acting oral anticoagulants (DOACs) in obese patients with venous thromboembolism (VTE).

MATERIAL AND METHODS

We used the data in the RIETE registry to compare the rates of VTE recurrences and major bleeding during long-term therapy with DOACs at recommended doses in patients with body mass index ≥30 kg/m2 (obese) vs. those with BMI 18.5-24.9 kg/m2 (normal weight). We performed regression models with competing risks for death.

RESULTS

From January 2013 through October 2022, 2885 obese patients and 2676 with normal weight in RIETE received rivaroxaban (n = 3020), apixaban (n = 1754), edoxaban (n = 636) or dabigatran (n = 151). Median age was 63 years and 52 % were female. At baseline, obese patients were more likely to have diabetes (18.6 % vs. 8.4 %), hypertension (51.9 % vs. 31.4 %) or pulmonary embolism (67.7 % vs. 61 %), and less likely to have renal insufficiency (5.3 % vs. 16 %) or anaemia (21.8 % vs. 28 %%). During anticoagulation (median, 147 vs. 101 days), the obese had a similar rate of VTE recurrences (1.71 vs. 2.14 events per 100 patients-years; hazard ratio (HR): 0.81; 95 % CI: 0.49-1.34) or major bleeding (1.45 vs. 1.76 per 100 patients-years; HR: 0.91; 95 % CI: 0.52-1.59) than those with normal weight. These findings persisted after multivariable analysis (recurrent VTE, HR: 0.80; 95 % CI: 0.48-1.32; major bleeding, HR: 1.11; 95 % CI: 0.60-2.07).

CONCLUSION

The use of DOACs at recommended doses in obese patients with VTE was associated with similar rates of VTE recurrences or major bleeding than in patients with normal weight.

Direct Oral Anticoagulants for the Treatment of Venous Thromboembolism in Obesity

Background: Direct oral anticoagulants (DOACs) are known to have similar efficacy with a decreased risk of bleeding when compared to warfarin for the treatment of venous thromboembolism (VTE). In patients with obesity, there are limited data regarding the safety and efficacy of DOACs. Despite concerns for both under- and over-dosing patients with extremes of body weight, there are no dose adjustment recommendations in the package inserts for any of the DOACs. Objective: To evaluate the safety and efficacy of DOACs versus warfarin for the treatment of VTE in patients with obesity. Methods: This single-center, retrospective cohort study included obese patients initiated on DOAC or warfarin therapy for VTE from January 2015 to January 2022. Patients with cancer, hypercoagulable disorders, end-stage kidney disease, or pregnancy were excluded. The primary endpoint was VTE recurrence. Secondary endpoints included major and minor bleeding. Results: A total of 120 patients met criteria for inclusion. Ninety-two received DOAC therapy and 28 received warfarin. The primary endpoint occurred in 4 patients in the DOAC group and 3 patients in the warfarin group (P = 0.35). Major bleeding occurred in 2 patients. Minor bleeding events occurred in 10 (8.33%) patients. Of those, 6 (6.5%) events occurred in patients receiving a DOAC and 4 (14.3%) events occurred in patients receiving warfarin (P = 0.28). Limitations of this study include the retrospective single-center study design. Conclusions: There was a comparable risk of bleeding and recurrent VTE between DOACs and warfarin in patients initiated on therapy for VTE.

Effectiveness and safety of non-vitamin K antagonist oral anticoagulant in the treatment of patients with morbid obesity or high body weight with venous thromboembolism: A meta-analysis

BACKGROUND

Venous thromboembolism (VTE) poses a significant health risk to patients with morbid obesity or high body weight. Non-vitamin K antagonist oral anticoagulants (NOACs) are emerging treatments, but their effectiveness and safety compared with vitamin K antagonists (VKAs) in this population are yet to be thoroughly studied.

METHODS

We conducted a systematic review and meta-analysis, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Four electronic databases were searched for relevant studies comparing the efficacy and safety of NOACs and VKAs in treating patients with VTE with a body mass index > 40 kg/m2 or body weight > 120 kg. Eligible studies were scored for quality using the Newcastle-Ottawa Scale.

RESULTS

Thirteen studies were included. The meta-analysis results showed that compared to VKAs, NOACs significantly decreased the risk of VTE occurrence (odds ratio = 0.72, 95% CI: 0.57-0.91, I2 = 0%, P < .001) and were associated with a lower risk of bleeding (odds ratio = 0.74, 95% CI: 0.58-0.95, I2 = 0%, P < .05). Subgroup analysis showed that in the cancer patient subgroup, both risks of VTE occurrence and bleeding were lower in the NOAC group than in the VKA group. In patients without cancer, the risk of VTE was significantly lower in the NOAC group.

CONCLUSION

NOACs appear to be more effective and safer than VKAs in patients with morbid obesity or a high body weight with VTE. However, further large-scale randomized controlled trials are required to confirm these findings.

DOACs use in extreme body-weighted patients: results from the prospective START-register

BACKGROUND

Direct oral anticoagulants (DOACs) are widely used for the treatment of venous thromboembolism (VTE) and for stroke prevention in atrial fibrillation (AF). However, evidence in obese and underweight patients is limited. We assessed the safety and effectiveness of DOACs and vitamin K antagonists (VKAs) in patients  ≥ 120 kg or ≤ 50 kg enrolled in an observational prospective cohort study, the START-Register.

METHODS

Adult patients started on anticoagulant therapy were followed up for a median of 1.5 years (IQR 0.6-2.8). Primary efficacy outcome was the occurrence of VTE recurrence, stroke and systemic embolism. Primary safety outcome was major bleeding (MB).

RESULTS

10,080 AF and VTE patients were enrolled between March 2011 and June 2021, 295 patients weighted  ≤ 50 kg and 82 patients ≥ 120 kg. Obese patients were significantly younger than underweight patients. Rates of thrombotic events were low and similar between DOACs and VKAs in underweight patients (1 event on DOACs therapy [0.9% 95% CI 0.11-5.39] and 2 on VKAs [1.1% 95% CI 0.01-47.68]) and in overweight patients (0 events on DOACs, 1 on VKAs [1.6%, 95% CI 0.11-5.79]. Two MB events occurred on DOACs (1.9%, 95% CI 0.38-6.00) and 3 on VKAs (1.6%, 95% CI 0.04-22.06) in the underweight group; 1 MB on DOACs (5.3% 95% CI 0.33-16.68) and 2 on VKAs (3.3%, 95% CI 0.02-130.77) in the overweight group.

CONCLUSIONS

DOACs seem to be effective and safe also for the treatment of patients with extreme body weights, both underweight and overweight. Further prospective studies are needed to support these findings.

Apixaban thromboprophylaxis in ambulatory patients with cancer and obesity: Insights from the AVERT trial

BACKGROUND

The use of direct oral anticoagulants (DOACs) in obese patients is uncertain. It is unclear if body mass index (BMI) affects the safety and efficacy of DOACs for the primary prevention of venous thromboembolism (VTE) in high-risk ambulatory patients with cancer. We sought to determine the outcomes associated with the use of apixaban for the primary prevention of cancer-associated VTE according to BMI.

METHODS

The randomized, double-blinded, placebo-controlled AVERT trial evaluated apixaban thromboprophylaxis in intermediate-to-high risk ambulatory cancer patients receiving chemotherapy. For this post-hoc analysis, the primary efficacy and safety outcomes were objectively confirmed VTE and clinically relevant bleeding (major and clinically relevant non-major bleeding), respectively. Obesity was defined as BMI ≥30 kg/m².

RESULTS

Among 574 patients randomized, 217 (37.8 %) patients had BMI ≥30 kg/m². Obese patients were overall younger, more likely to be female, had higher creatinine clearance and hemoglobin, lower platelet count, and better ECOG performance status. Compared to placebo, apixaban thromboprophylaxis was associated with reduced VTE in both obese (hazard ratio [HR] 0.26; 95 % confidence interval [CI], 0.14-0.46; p < 0.0001) and non-obese (HR 0.54; 95%CI, 0.29-1.00; p = 0.049) patients. The HR for clinically relevant bleeding (apixaban vs. placebo) was numerically higher in obese (2.09; 95%CI, 0.96-4.51; p = 0.062) than non-obese subjects (1.23; 95%CI, 0.71-2.13; p = 0.46), but overall in line with the risks observed in the general trial population.

CONCLUSIONS

In the AVERT trial enrolling ambulatory cancer patients receiving chemotherapy, we found no substantial differences in the efficacy or safety of apixaban thromboprophylaxis across obese and non-obese subjects.

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.

Direct Oral Anticoagulants in Obese Patients with Venous Thromboembolism: Results of an Expert Consensus Panel

In clinical practice, direct oral anticoagulants (DOACs) are increasingly used for venous thromboembolism treatment and prevention. A substantial proportion of patients with venous thromboembolism are also obese. International guidance published in 2016 stated that DOACs could be used in standard doses in patients with obesity up to a body mass index [BMI] of 40 kg/m², but should not be used in those with severe obesity (BMI > 40 kg/m²) owing to limited supporting data at the time. Although updated guidance in 2021 removed this limitation, some healthcare providers still avoid DOACs even in patients with lower levels of obesity. Furthermore, there are still evidence gaps regarding treatment of severe obesity, the role of peak and trough DOAC levels in these patients, use of DOACs after bariatric surgery, and appropriateness of DOAC dose reduction in the setting of secondary venous thromboembolism prevention. This document describes proceedings and outcomes of a multidisciplinary panel convened to review these and other key issues regarding DOAC use for treatment or prevention of venous thromboembolism in individuals with obesity.

Dilemmas Related to Direct-Acting Oral Anticoagulant Administration in Patients With Extreme Obesity

OBJECTIVE

The objective of the study was to discuss the controversies surrounding the use and dosing of direct-acting oral anticoagulants (DOACs) in obese patients recognizing the limitations of the existing evidence base that preclude strong recommendations.

DATA SOURCES

A literature search of MEDLINE was performed (2020 to end August 2022) subsequent to recent guidelines using the following search terms: direct acting anticoagulants, obesity, rivaroxaban, apixaban, edoxaban, dabigatran, dabigatran etexilate, and clinical practice guidelines.

STUDY SELECTION AND DATA ABSTRACTION

English-language studies and those conducted in adults were selected.

DATA SYNTHESIS

The available randomized studies evaluating DOACs had relatively small numbers of patients with more extreme forms of obesity (body mass index [BMI] > 40 kg/m²) and none of the larger studies had a specific focus on dosing DOACs in obese patients. Recent guidelines by the International Society on Thrombosis and Haemostasis (ISTH) have specific recommendations for dosing DOACs in obesity. There are pharmacokinetic/pharmacodynamic and observational studies published before and after the ISTH guidelines with a focus on DOAC dosing in obese patients that generally support the recommendations in the guidelines, but most involved small numbers of patients usually with BMIs <45 kg/m².

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review discusses DOAC dosing in obesity with important considerations for clinicians related to DOAC choice and dosing.

CONCLUSIONS

Dosing alterations of DOACs do not appear to be necessary when used for either prophylaxis or treatment in patients with BMIs up to approximately 45 to 50 kg/m², but research is needed for BMIs >50 kg/m².