Efficacy, Safety, and Exposure of Apixaban in Patients with High Body Weight or Obesity and Venous Thromboembolism: Insights from AMPLIFY

Controversies and challenges of anticoagulation therapy in obesity

INTRODUCTION

The relationship between anticoagulation efficacy and safety in obesity is complex and can vary between degrees of obesity and anticoagulant choice. Indeed, patients at extremes of body weight were under-represented in randomized trials. Additionally, the possibility of an 'obesity paradox' has been raised in atrial fibrillation, describing decreased thromboembolic risk in obese patients.

AREAS COVERED

We explore the current literature on anticoagulation in obesity, specifically with regard to efficacy in atrial fibrillation, efficacy in venous thromboembolism, and bleeding risk. Pharmacodynamic and pharmacokinetic considerations are also discussed.

EXPERT OPINION

As a class, direct oral anticoagulants are comparable to vitamin-K antagonists in preventing and treating thromboembolism in overweight and obese patients, whilst not increasing bleeding risk.

Anticoagulation approach in morbid obesity: a comprehensive review on venous thromboembolism management

Obesity is a recognized risk factor for venous thromboembolism (VTE), associated with distinct challenges in managing anticoagulation therapy. There is still limited evidence regarding the impact of extreme body weight on the pharmacokinetics, pharmacodynamics, efficacy, and safety of various anticoagulant medications. To our knowledge, this is the first comprehensive review to address both prophylactic and therapeutic anticoagulant dosages specifically for managing VTE in patients with a body mass index (BMI) ≥40 kg/m2 or weight ≥120 kg. Our aim was to synthesize the findings of relevant studies alongside the latest recommendations on anticoagulation in this unique population. We gathered and analyzed data on all classes of anticoagulants available for VTE management, including vitamin K antagonists (VKAs), unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), fondaparinux, and direct oral anticoagulants (DOACs), offering insights into their efficacy and safety profiles. Additionally, we explored special subpopulations of morbidly obese patients, such as those with cancer, renal dysfunction, or those undergoing bariatric surgery, recognizing the nuanced therapeutic challenges they present. The current evidence for anticoagulant therapy in morbidly obese patients with VTE is evidently insufficient, underscoring the need for a tailored approach and meticulous monitoring to achieve an optimal therapeutic balance.

Treatment of atrial fibrillation and venous thromboembolism with factor Xa inhibitors in severely obese patients

BACKGROUND

A paucity of data exists to support the use of factor (F)Xa inhibitors in severely obese patients with a weight of ≥150 kg or body mass index (BMI) of ≥50 kg/m2.

OBJECTIVES

The purpose of this study was to evaluate whether FXa inhibitors are as safe and effective as warfarin for the treatment of atrial fibrillation (AF) and/or venous thromboembolism (VTE) in individuals with a BMI of ≥50 kg/m2 and/or weight of ≥150 kg.

METHODS

This was a multicenter retrospective cohort study of severely obese adult patients with AF and/or VTE treated with a FXa inhibitor or warfarin. The primary effectiveness outcome was composite odds of stroke, systemic embolism, or VTE; the primary safety outcome was odds of major bleeding. Secondary outcomes included incidence of stroke or systemic embolism, VTE, major bleeding, clinically relevant nonmajor bleeding, all-cause mortality, change in anticoagulation, and total number of hospital encounters. Outcomes were assessed for 12 months following initiation of study drug.

RESULTS

A total of 1736 patients were included. The mean weight and BMI of the overall cohort were 164.4 kg and 54.6 kg/m2, respectively. There was no difference in odds of stroke, systemic embolism or VTE (odds ratio, 1.005; 95% CI, 0.6-1.68), or major bleeding (odds ratio, 0.9; 95% CI, 0.47-1.7) between groups.

CONCLUSION

These data suggest that apixaban and rivaroxaban are safe and effective alternatives to warfarin for the treatment of AF and/or VTE in individuals with a BMI of ≥50 kg/m2 and/or weight of ≥150 kg.

Update on antithrombotic therapy and body mass: a clinical consensus statement of the European Society of Cardiology Working Group on Cardiovascular Pharmacotherapy and the European Society of Cardiology Working Group on Thrombosis

Obesity and underweight are a growing health problem worldwide and a challenge for clinicians concerning antithrombotic therapy, due to the associated risks of thrombosis and/or bleeding. This clinical consensus statement updates a previous one published in 2018, by reviewing the most recent evidence on antithrombotic drugs based on body size categories according to the World Health Organization classification. The document focuses mostly on individuals at the extremes of body weight, i.e. underweight and moderate-to-morbid obesity, who require antithrombotic drugs, according to current guidelines, for the treatment or prevention of cardiovascular diseases or venous thromboembolism. Managing antithrombotic therapy or thromboprophylaxis in these individuals is challenging, due to profound changes in body composition, metabolism and organ function, and altered drug pharmacokinetics and pharmacodynamics, as well as weak or no evidence from clinical trials. The document also includes artificial intelligence simulations derived from in silico pharmacokinetic/pharmacodynamic models, which can mimic the pharmacokinetic changes and help identify optimal regimens of antithrombotic drugs for severely underweight or severely obese individuals. Further, bariatric surgery in morbidly obese subjects is frequently performed worldwide. Bariatric surgery causes specific and additional changes in metabolism and gastrointestinal anatomy, depending on the type of the procedure, which can also impact the pharmacokinetics of antithrombotic drugs and their management. Based on existing literature, the document provides consensus statements on optimizing antithrombotic drug management for underweight and all classes of obese patients, while highlighting the current gaps in knowledge in these complex clinical settings, which require personalized medicine and precision pharmacology.

Apixaban versus low molecular weight heparin in patients with cancer-associated venous thromboembolism: a systematic review and meta-analysis

Background

The optimal treatment regimen for patients with cancer-associated venous thromboembolism (CA-VTE) remains unclear. Therefore, the authors sought to compare the outcomes of (VKAs) versus direct apixaban and low molecular weight heparin (LMWH) in patients with CA-VTE.

Methods

MEDLINE, Embase, and Cochrane Central databases were searched for randomized controlled trials (RCTs) and observational studies comparing the efficacy and safety of apixaban and LMWH in patients with CA-VTE. Major bleeding, clinically relevant non-major bleeding (CRNMB), recurrence of pulmonary embolism (PE), deep venous thrombosis (DVT) and bleeding-related mortality were among outcomes of interest. Mantel-Haenszel weighted random-effects model was used to calculate relative risks (RRs) with 95% CIs.

Results

The analysis included 12 011 patients from 3 RCTs and 2 observational studies. Compared to LMWH, apixaban significantly decreased the risk of major bleeding [RR 0.67 (95% CI 0.54, 0.83); P=0.0003, I2=0%] without significantly changing the risk of clinically relevant non-major bleeding [RR 0.96 (95% CI 0.64, 0.1.45); P=0.85, I2=57%]. Patients on apixaban had a noticeably reduced the risk of recurrence of PE than those taking LMWH, according to a meta-analysis [RR 0.56 (95% CI 0.32, 0.99); P=0.05, I2=0%]. There was no discernible difference between apixaban and LMWH in bleeding-related mortality events [RR 0.20 (95% CI 0.01, 4.18); P=0.30, I2=NA%], and recurrence of DVT [RR 0.60 (95% CI 0.22, 1.59); P=0.23, I2=32%].

Conclusion

Due to its lower risk of severe bleeding and reduced PE recurrence, apixaban may be a preferable treatment option for CA-VTE, but additional research is required to validate these conclusions and evaluate its long-term efficacy and safety.

Direct Oral Anticoagulants for Pulmonary Embolism

Venous thromboembolism (VTE) is the third most common cardiovascular disease. For most patients, the standard of treatment has long consisted on low-molecular-weight heparin followed by vitamin K antagonists, but a number of clinical trials and, subsequently, post-marketing studies have shown that direct oral anticoagulants (DOACs) with or without lead-in heparin therapy are effective alternatives with fewer adverse effects. This evidence has led to important changes in the guidelines on the treatment of VTE, including pulmonary embolism (PE), with the DOACs being now recommended as the first therapeutic choice. Additional research has contributed to identifying low-risk PE patients who can benefit from outpatient management or from early discharge from the emergency department with DOAC treatment. There is evidence to support the use of DOACs in intermediate-risk PE patients as well as in high-risk patients receiving thrombolytic treatment. The use of DOACs has also been proven to be safe and effective in special populations of PE patients, such as patients with renal impairment, liver impairment, and cancer.

Obese patients with atrial fibrillation are more efficiently protected from thrombosis under warfarin or xabans compared to non-obese patients; a systematic review and Meta-analysis of six randomized controlled trials

INTRODUCTION

Recommendations about proper anticoagulation in obese patients, body mass index (BMI) > 30 kg/m2, are not yet clearly defined. Obese patients were included in randomized controlled trials comparing new anticoagulants (NOACs) with warfarin in patients with atrial fibrillation or thromboembolism.

METHODS

We performed a medline search entering proper criteria and finally 6 post-hoc analysis of RCTs, reporting outcome according to BMI, were included in this meta-analysis. Two major outcomes were considered end points in our meta-analysis; thrombosis, including ischemic cerebral events (transient or not) and venous thrombosis (DVD) /pulmonary embolism (PE) and bleeding, including major bleeding and clinically relevant non-major bleeding.

RESULTS

In the NOACs treated group, thrombosis occurred less frequently in obese vs non-obese patients; RR and 95 % CI 0,75 (0,58-0,97), p = 0,03, while low heterogeneity was observed (I2= 40 %). In the warfarin treated subgroup there was statistically significant difference with less thrombotic events occurring in the obese vs non-obese patients; RR and (95 % CI) 0,80 (0,66-0,98), p = 0,03, and heterogeneity was low (I2 = 24 %). This protective effect called the obesity paradox is limited to obese patients anticoagulated for non-valvular atrial fibrillation (NVAF); RR (95 % CI) was 0,70 (0,58-0,85) p = 0,03 and I2 = 24 %. Bleeding events were similar under both NOACs and warfarin in obese vs non-obese analysis.

CONCLUSIONS

Obese patients anticoagulated for NVAF with either standard dose of xabans or INR guided warfarin are more efficiently protected against thrombosis compared to non-obese patients.

Safety and Efficacy of Direct Oral Anticoagulants vs Warfarin in Patients With Obesity and Venous Thromboembolism: A Retrospective Analysis

BACKGROUND

Current venous thromboembolism guidelines recommend using direct oral anticoagulants (DOACs) over warfarin regardless of obesity status; however, evidence remains limited for the safety and efficacy of DOAC use in patients with obesity. This retrospective analysis sought to demonstrate the safety and efficacy of DOACs compared with warfarin in a diverse population of patients with obesity in light of current prescribing practices.

METHODS

A retrospective cohort study was conducted at a large academic health system between July 2014 and September 2019. Adults with an admission diagnosis of deep vein thrombosis (DVT) or pulmonary embolism, with weight greater than 120 kg or a body mass index greater than 40, and who were discharged on an oral anticoagulant were included. Outcomes included occurrence of a thromboembolic event (DVT, pulmonary embolism, or ischemic stroke), bleeding event requiring hospitalization, and all-cause mortality within 12 months following index admission.

RESULTS

Out of 787 patients included, 520 were in the DOAC group and 267 were in the warfarin group. Within 12 months of index hospitalization, thromboembolic events occurred in 4.23% of patients in the DOAC group vs 7.12% of patients in the warfarin group (hazard ratio, 0.6 [95% CI, 0.32-1.1]; P = .082). Bleeding events requiring hospitalization occurred in 8.85% of DOAC patients vs 10.1% of warfarin patients (hazard ratio, 0.93 [95% CI, 0.57-1.5]; P = .82). A DVT occurred in 1.7% and 4.9% of patients in the DOAC and warfarin groups, respectively (hazard ratio, 0.35 [95% CI, 0.15-0.84]; P = .046).

CONCLUSION

No significant differences could be determined between DOACs and warfarin for cumulative thromboembolic or bleeding events, pulmonary embolism, ischemic stroke, or all-cause mortality. The risk of DVT was lower with apixaban and rivaroxaban. Regardless of patient weight or body mass index, physicians prescribed DOACs more commonly than warfarin.

Retrospective, multicenter analysis of the safety and effectiveness of direct oral anticoagulants for the treatment of venous thromboembolism in obesity

BACKGROUND

Direct oral anticoagulants (DOACs) are the preferred treatment for venous thromboembolism (VTE). However, DOAC use in patients with a BMI greater than 40 kg/m2 has not been well studied despite the growing prevalence of obesity, and current literature is often underpowered.

METHODS

This multicenter, retrospective, observational study evaluated patients 18 years and older who received DOACs for acute VTE treatment. Patients receiving DOACs for recurrent VTE or for failure of another agent were excluded. The primary efficacy outcome was recurrent VTE and the primary safety outcome was major bleeding within 12 months (or one month after stopping anticoagulation therapy). A propensity score analysis was performed to balance patient characteristics and evaluate the primary endpoints by BMI group. Time-to-event outcomes were analyzed using weighted Kaplan-Meier curves.

RESULTS

There were 165 patients with a BMI of at least 40 kg/m2 and 320 patients with a BMI less than 40 kg/m2. The majority received apixaban (373, 77%). Recurrent VTE occurred in 5 (3.0%) and 13 (4.1%) of patients in the higher and lower BMI groups, respectively (adjusted OR: 0.66; 95% CI: 0.16-2.69). Major bleeding occurred in 5 (3.0%) and 15 (4.7%) of patients in the higher and lower BMI groups, respectively (adjusted OR: 1.19; 95% CI: 0.36-3.92).

CONCLUSION

There was no significant difference in VTE recurrence or major bleeding related to BMI among patients treated with DOACs. This study showed that DOACs may be a safe and effective VTE treatment option in patients with obesity.

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-Acting Oral Anticoagulants in patients at extremes of body weight: a review of pharmacological considerations and clinical implications

Patients at extremes of body weight are underrepresented in randomized controlled trials of direct-acting oral anticoagulants (DOACs). Therefore, their optimal anticoagulant treatment remains a topic of debate. The aim of this narrative review is to summarize the evidence on the pharmacokinetic and pharmacodynamic profile of DOACs for treating patients at extremes of body weight in venous thromboembolism (VTE) and in the prevention of cardioembolic stroke in nonvalvular atrial fibrillation (NVAF). A literature search was conducted in the main bibliographic databases, and the most relevant reviews and original articles on the topic were selected. Although data in these patient groups are limited, apixaban and rivaroxaban show a favorable pharmacokinetic and pharmacodynamic profile in obese VTE treatment and NVAF patients and, in the case of apixaban, also in underweight patients. In particular, these drugs demonstrated comparable efficacy and safety to standard therapy. Very few data were available for dabigatran and edoxaban; the latter drug was safer at a lower dose, mainly in underweight patients. Our findings are in line with the last International Society of Haemostasis and Thrombosis position paper and European Heart Rhythm Association 2021 practical guide, suggesting the use of apixaban and rivaroxaban in morbidly obese patients (>120 kg or body mass index ≥40 kg/m 2 ) and the reduced dosage of edoxaban in low-weight patients. Future studies should focus on large populations of patients at extremes of body weights to acquire more clinical and pharmacokinetic evidence on all available DOACs, especially those currently less investigated.

Pharmacokinetics and pharmacodynamics of direct oral anticoagulants

INTRODUCTION

Direct oral anticoagulants (DOACs) have overtaken vitamin K antagonists to become the most widely used method of anticoagulation for most indications. Their stable and predictable pharmacokinetics combined with relatively simple dosing, and the absence of routine monitoring has made them an attractive proposition for healthcare providers. Despite the benefits of DOACs as a class, important differences exist between individual DOAC drugs in respect of their pharmacokinetic and pharmacodynamic profiles with implications for dosing and reversal in cases of major bleeding.

AREAS COVERED

This review summarizes the state of knowledge relating to the pharmacokinetics of dabigatran (factor IIa/thrombin inhibitor) and apixaban, edoxaban and rivaroxaban (factor Xa) inhibitors. We focus on pharmacokinetic differences between the drugs which may have clinically significant implications.

EXPERT OPINION

Patient-centered care necessitates a careful consideration of the pharmacokinetic and pharmacodynamic differences between DOACs, and how these relate to individual patient circumstances. Prescribers should be aware of the potential for pharmacokinetic drug interactions with DOACs which may influence prescribing decisions in patients with multiple comorbidities. In order to give an appropriate dose of DOAC drugs, accurate estimation of renal function using the Cockcroft-Gault formula using actual body weight is necessary. An increasing body of evidence supports the use of DOACs in patients who are obese, and this is becoming more routine in clinical practice.

Use of direct oral anticoagulants for venous thromboembolism treatment at extremes of body weight, renal and liver function: an illustrated review

Direct oral anticoagulants (DOACs) have been a welcome addition to clinical practice due to the practical advantages they confer over traditional anticoagulants. In many countries, DOACs are now used as first-line treatment for the management of venous thromboembolism (VTE). Traditional anticoagulants allow for a degree of individualization, either through monitoring the international normalized ratio in the case of vitamin-K antagonists or through dose titration according to bodyweight in the case of low-molecular-weight heparin. However, the use of fixed doses and removal of the need for routine monitoring has created uncertainty in prescribing DOACs for patients at the extremes of bodyweight, renal function, and patients with liver impairment, who were not well represented in the DOAC licensing clinical trials. The discipline of pharmacokinetics is concerned with the movement of drugs through the body. Although the extremes of bodyweight and renal and liver function will influence the pharmacokinetics of DOACs, are these changes significant enough to affect clinical outcomes of bleeding and thrombosis? In other words, can the fixed-dosing strategy of DOACs accommodate these differences in physiology? In this review, we recap key pharmacokinetic principles for drug dosing; review venous thromboembolism trial and real-world data on patients prescribed DOACs at the extremes of bodyweight, renal function, and liver function; relate this to the pharmacokinetic properties of DOACs; and summarize the state of the field and current unknowns.

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.

Oral direct thrombin inhibitors or oral factor Xa inhibitors versus conventional anticoagulants for the treatment of pulmonary embolism

BACKGROUND

Pulmonary embolism (PE) is a potentially life-threatening condition in which a clot can migrate from the deep veins, most commonly in the leg, to the lungs. Conventional treatment of PE used unfractionated heparin (UFH), low molecular weight heparin (LMWH), fondaparinux, and vitamin K antagonists (VKAs). Recently, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTIs) and oral factor Xa inhibitors. DOACs have characteristics that may be favourable to conventional treatment, including oral administration, a predictable effect, no need for frequent monitoring or re-dosing, and few known drug interactions. This review reports the efficacy and safety of these drugs in the long-term treatment of PE (minimum duration of three months). This is an update of a Cochrane Review first published in 2015.  OBJECTIVES: To assess the efficacy and safety of oral DTIs and oral factor Xa inhibitors versus conventional anticoagulants for the long-term treatment of PE.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases, the World Health Organization International Clinical Trials Registry Platform and the ClinicalTrials.gov trials registers to 2 March 2022. We checked the reference lists of relevant articles for additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which people with a PE confirmed by standard imaging techniques were allocated to receive an oral DTI or an oral factor Xa inhibitor compared with a conventional anticoagulant or compared with each other for the long-term treatment of PE (minimum duration three months).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were recurrent PE, recurrent venous thromboembolism (VTE), and deep vein thrombosis (DVT). Secondary outcomes were all-cause mortality, major bleeding, and health-related quality of life. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified five additional RCTs with 1484 participants for this update. Together with the previously included trials, we have included ten RCTs with a total of 13,073 participants. Two studies investigated an oral DTI (dabigatran) and eight studies investigated oral factor Xa inhibitors (three rivaroxaban, three apixaban, and two edoxaban). The studies were of good methodological quality overall.  Meta-analysis showed no clear difference in the efficacy and safety of oral DTI compared with conventional anticoagulation in preventing recurrent PE (odds ratio (OR) 1.02, 95% confidence interval (CI) 0.50 to 2.04; 2 studies, 1602 participants; moderate-certainty evidence), recurrent VTE (OR 0.93, 95% CI 0.52 to 1.66; 2 studies, 1602 participants; moderate-certainty evidence), DVT (OR 0.79, 95% CI 0.29 to 2.13; 2 studies, 1602 participants; moderate-certainty evidence), and major bleeding (OR 0.50, 95% CI 0.15 to 1.68; 2 studies, 1527 participants; moderate-certainty evidence). We downgraded the certainty of evidence by one level for imprecision due to the low number of events. There was also no clear difference between the oral factor Xa inhibitors and conventional anticoagulation in the prevention of recurrent PE (OR 0.92, 95% CI 0.66 to 1.29; 3 studies, 8186 participants; moderate-certainty evidence), recurrent VTE (OR 0.83, 95% CI 0.66 to 1.03; 8 studies, 11,416 participants; moderate-certainty evidence), DVT (OR 0.77, 95% CI 0.48 to 1.25; 2 studies, 8151 participants; moderate-certainty evidence), all-cause mortality (OR 1.16, 95% CI 0.79 to 1.70; 1 study, 4817 participants; moderate-certainty evidence) and major bleeding (OR 0.71, 95% CI 0.36 to 1.41; 8 studies, 11,447 participants; low-certainty evidence); the heterogeneity for major bleeding was significant (I2 = 79%). We downgraded the certainty of the evidence to moderate and low because of imprecision due to the low number of events and inconsistency due to clinical heterogeneity. None of the included studies measured health-related quality of life.

AUTHORS' CONCLUSIONS

Available evidence shows there is probably little or no difference between DOACs and conventional anticoagulation in the prevention of recurrent PE, recurrent VTE, DVT, all-cause mortality, and major bleeding. The certainty of evidence was moderate or low. Future large clinical trials are required to identify if individual drugs differ in effectiveness and bleeding risk, and to explore effect differences in subgroups, including people with cancer and obesity.

Oral direct thrombin inhibitors or oral factor Xa inhibitors versus conventional anticoagulants for the treatment of deep vein thrombosis

BACKGROUND

Deep vein thrombosis (DVT) is a condition in which a clot forms in the deep veins, most commonly of the leg. It occurs in approximately one in 1000 people. If left untreated, the clot can travel up to the lungs and cause a potentially life-threatening pulmonary embolism (PE). Previously, a DVT was treated with the anticoagulants heparin and vitamin K antagonists. However, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTIs) and oral factor Xa inhibitors, which have characteristics that may be favourable compared to conventional treatment, including oral administration, a predictable effect, lack of frequent monitoring or dose adjustment and few known drug interactions. DOACs are now commonly being used for treating DVT: recent guidelines recommended DOACs over conventional anticoagulants for both DVT and PE treatment. This Cochrane Review was first published in 2015. It was the first systematic review to measure the effectiveness and safety of these drugs in the treatment of DVT. This is an update of the 2015 review.  OBJECTIVES: To assess the effectiveness and safety of oral DTIs and oral factor Xa inhibitors versus conventional anticoagulants for the long-term treatment of DVT.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 1 March 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which people with a DVT, confirmed by standard imaging techniques, were allocated to receive an oral DTI or an oral factor Xa inhibitor compared with conventional anticoagulation or compared with each other for the treatment of DVT.  DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were recurrent venous thromboembolism (VTE), recurrent DVT and PE. Secondary outcomes included all-cause mortality, major bleeding, post-thrombotic syndrome (PTS) and quality of life (QoL). We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified 10 new studies with 2950 participants for this update. In total, we included 21 RCTs involving 30,895 participants. Three studies investigated oral DTIs (two dabigatran and one ximelagatran), 17 investigated oral factor Xa inhibitors (eight rivaroxaban, five apixaban and four edoxaban) and one three-arm trial investigated both a DTI (dabigatran) and factor Xa inhibitor (rivaroxaban). Overall, the studies were of good methodological quality. Meta-analysis comparing DTIs to conventional anticoagulation showed no clear difference in the rate of recurrent VTE (odds ratio (OR) 1.17, 95% confidence interval (CI) 0.83 to 1.65; 3 studies, 5994 participants; moderate-certainty evidence), recurrent DVT (OR 1.11, 95% CI 0.74 to 1.66; 3 studies, 5994 participants; moderate-certainty evidence), fatal PE (OR 1.32, 95% CI 0.29 to 6.02; 3 studies, 5994 participants; moderate-certainty evidence), non-fatal PE (OR 1.29, 95% CI 0.64 to 2.59; 3 studies, 5994 participants; moderate-certainty evidence) or all-cause mortality (OR 0.66, 95% CI 0.41 to 1.08; 1 study, 2489 participants; moderate-certainty evidence). DTIs reduced the rate of major bleeding (OR 0.58, 95% CI 0.38 to 0.89; 3 studies, 5994 participants; high-certainty evidence).   For oral factor Xa inhibitors compared with conventional anticoagulation, meta-analysis demonstrated no clear difference in recurrent VTE (OR 0.85, 95% CI 0.71 to 1.01; 13 studies, 17,505 participants; moderate-certainty evidence), recurrent DVT (OR 0.70, 95% CI 0.49 to 1.01; 9 studies, 16,439 participants; moderate-certainty evidence), fatal PE (OR 1.18, 95% CI 0.69 to 2.02; 6 studies, 15,082 participants; moderate-certainty evidence), non-fatal PE (OR 0.93, 95% CI 0.68 to 1.27; 7 studies, 15,166 participants; moderate-certainty evidence) or all-cause mortality (OR 0.87, 95% CI 0.67 to 1.14; 9 studies, 10,770 participants; moderate-certainty evidence). Meta-analysis showed a reduced rate of major bleeding with oral factor Xa inhibitors compared with conventional anticoagulation (OR 0.63, 95% CI 0.45 to 0.89; 17 studies, 18,066 participants; high-certainty evidence).  AUTHORS' CONCLUSIONS: The current review suggests that DOACs may be superior to conventional therapy in terms of safety (major bleeding), and are probably equivalent in terms of efficacy. There is probably little or no difference between DOACs and conventional anticoagulation in the prevention of recurrent VTE, recurrent DVT, pulmonary embolism and all-cause mortality. DOACs reduced the rate of major bleeding compared to conventional anticoagulation. The certainty of evidence was moderate or high.

Factor Xa inhibitors versus vitamin K antagonist in morbidly obese patients with venous thromboembolism: a systematic review and meta-analysis

INTRODUCTION

Guidelines have endorsed non-vitamin K antagonist oral anticoagulants (NOACs), consisting of factor Xa inhibitors (xabans) and direct thrombin inhibitors, as the first line of treatment in venous thromboembolism (VTE) and atrial fibrillation. However, morbidly obese patients were under-represented in landmark trials of NOACs. Therefore, this study aimed to systematically review and perform a meta-analysis of studies on xabans versus vitamin K antagonist (VKA) in this high-risk population with VTE.

METHODS

PubMed, Embase, Medline, Cochrane library, and Google Scholar databases were searched to identify studies that compared xabans and VKA in treating morbidly obese patients with VTE. Morbid obesity was defined as body weight ≥ 120 kg or BMI ≥ 40 kg/m². Outcomes of interest included recurrent VTE, major bleeding, and clinically relevant non-major bleeding (CRNMB).

RESULTS

Eight studies comprising 30,895 patients were included. A total of 12,755 patients received xabans while 18,140 received VKAs. No significant difference in the odds of recurrent VTE (OR 0.75, 95% CI 0.55-1.01) and CRNMB (OR 0.69, 95% CI 0.44-1.09) was observed between the xabans group and the VKA group. However, the xabans group was associated with lower odds of major bleeding (OR 0.70, 95% CI 0.59-0.83).

CONCLUSION

Xabans have lower odds of major bleeding but similar odds of recurrent VTE when compared with VKAs in treating VTE in morbidly obese patients. Large registry analyses or future randomized controlled trials will be helpful in confirming these findings.

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.

Pharmacokinetics and Dosing Regimens of Direct Oral Anticoagulants in Morbidly Obese Patients: An Updated Literature Review

Data on the impact of morbid obesity (body mass index [BMI] ≥ 40 kg/m²) on the pharmacokinetics (PK), pharmacodynamics (PD) of direct oral anticoagulants (DOACs) are relatively limited, making it difficult to design optimal dosing regimens in morbidly obese patients.To review literature on PK/PD profile, efficacy, and safety of DOACs in venous thromboembolism (VTE) and nonvalvular atrial fibrillation (AF) patients with morbid obesity and make recommendations regarding optimal dosing regimens in these patient populations.A detailed literature search was conducted (from inception to June 22, 2022) for relevant articles involving PK/PD and clinical data on DOACs use in morbidly obese patients with VTE or AF, or healthy volunteers.A total of 28 studies were identified. DOAC-specific PK variations and clinical outcomes have been observed. Obesity may have a modest effect on PK/PD of dabigatran, apixaban, or rivaroxaban. Dabigatran was effective in AF patients with morbid obesity but might increase the risk of gastrointestinal bleeding. Standard dosing of apixaban or rivaroxaban is effective and safe for VTE and AF patients with morbid obesity. Trough edoxaban concentration and anti-Xa activity were similar in different BMI groups (18.5 to >40 kg/m²), and standard dosing of edoxaban may be effective and safe for AF patients.Current evidence suggests dabigatran should be used with caution in patients with AF as it might increase the risk of gastrointestinal bleeding; Standard dosing of apixaban or rivaroxaban can be used in VTE or AF patients; Standard dosing of edoxaban may be considered in AF patients.

Risk and Management of Bleeding Complications with Direct Oral Anticoagulants in Patients with Atrial Fibrillation and Venous Thromboembolism: a Narrative Review

Atrial fibrillation (AF) and venous thromboembolism (VTE) are highly prevalent conditions with a significant healthcare burden, and represent the main indications for anticoagulation. Direct oral anticoagulants (DOACs) are the first choice treatment of AF/VTE, and have become the most prescribed class of anticoagulants globally, overtaking vitamin K antagonists (VKAs). Compared to VKAs, DOACs have a similar or better efficacy/safety profile, with reduced risk of intracerebral hemorrhage (ICH), while the risk of major bleeding and other bleeding harms may vary depending on the type of DOAC. We have critically reviewed available evidence from randomized controlled trials and observational studies regarding the risk of bleeding complications of DOACs compared to VKAs in patients with AF and VTE. Special patient populations (e.g., elderly, extreme body weights, chronic kidney disease) have specifically been addressed. Management of bleeding complications and possible resumption of anticoagulation, in particular after ICH and gastrointestinal bleeding, are also discussed. Finally, some suggestions are provided to choose the optimal DOAC to minimize adverse events according to individual patient characteristics and bleeding risk.

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.

Apixaban Use in Obese Patients: A Review of the Pharmacokinetic, Interventional, and Observational Study Data

Abstract

Relatively little is known about the influence of extreme body weight on the pharmacokinetics (PK), pharmacodynamics (PD), efficacy, and safety of drugs used in many disease states. While direct oral anticoagulants (DOACs) have an advantage over warfarin in that they do not require routine drug monitoring, some may regard this convenience as less compelling in obese patients. Some consensus guidelines discourage using DOACs in patients weighing > 120 kg or with a body mass index > 35–40 kg/m², given a sparsity of available data in this population and the concern that fixed dosing in obese patients might lead to decreased drug exposure and lower efficacy. Per the prescribing information, apixaban does not require dose adjustment in patients weighing above a certain threshold (e.g., ≥ 120 kg). Data from healthy volunteers and patients with nonvalvular atrial fibrillation (NVAF) or venous thromboembolism (VTE) have shown that increased body weight has a modest effect on apixaban’s PK. However, the paucity of exposure data in individuals > 120 kg and the lack of guideline consensus on DOAC use in obese patients continue to raise concerns about potential decreased drug exposure at extreme weight. This article is the first to comprehensively review the available PK data in obese individuals without NVAF or VTE, and PK, PD, efficacy, effectiveness, and safety data for apixaban in obese patients with either NVAF or VTE, including subgroup analyses across randomized controlled trials and observational (real-world) studies. These data suggest that obesity does not substantially influence the efficacy, effectiveness, or safety of apixaban in these patients.

Trial Registration ARISTOTLE: NCT00412984; AVERROES: NCT00496769; AMPLIFY: NCT00643201; AMPLIFY-EXT: NCT00633893; ADVANCE-1: NCT00371683; ADVANCE-2: NCT00452530; ADVANCE-3: NCT00423319

Video abstract

Safety and efficacy of direct oral anticoagulants in comparison with warfarin across different BMI ranges: A systematic review and meta-analysis

Background

Many publications have compared various outcomes defining safety and efficacy of DOACs across different BMI ranges. Our meta-analysis compares warfarin and DOACs for its treatment effects over different BMI ranges.

Methods

A systematic search was conducted from inception to May 2021 on PubMed, Scopus and Embase databases. The data was extracted and pooled using a random effects model. Our study consisted of patients being treated for VTE and AF, across different BMI categories. For the comparison of DOAC, risk ratios (RR) with 95% confidence intervals (CIs) were used, whilst for the second comparison between warfarin and DOACs odds ratios (OR) were used.

Results

In our first comparison, 12 studies (n = 254,908 patients) were included. For our second comparison, six studies (n = 109,609 patients) were included. Major bleeding events in the underweight group were higher than normal weight [RR: 1.89 (1.10, 3.23); P = 0.02; I² = 0%]. Overweight patients were related with reduced rates of VTE than in patients with normal BMI [RR: 0.86 (0.76, 0.97); P = 0.02; I² = 0%]. In comparison with patients receiving warfarin, DOACs had significantly reduced risk of major bleeding in normal weight, overweight and obese [OR: 0.64 (0.49, 0.83); P = 0.0007 I² = 90%].

Conclusion

The risk of VTE reduces with an increasing BMI, hence there could be a possible obesity paradox in patients with anticoagulation therapy. In comparison to warfarin, DOACs proved to be the safer option by having a reduced risk of bleeding across all BMI categories.

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Warfarin therapy and its effectiveness for prevention of thromboembolism.

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Effect of warfarin and DOACs over different BMI ranges.

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Safety and efficacy of DOACs across different BMI ranges.

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Lower risk of bleeding in normal weight, overweight, and obese patients with DOACs.

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Warfarin and DOACs across different BMI categories in VTE and AF patients.

Observed Apixaban Anti-Xa Levels in Obese Patients

BACKGROUND

Recent guidelines suggest that, for venous thromboembolism (VTE), standard doses of apixaban are appropriate in patients with body mass index (BMI) >40 kg/m2 or >120 kg. Atrial fibrillation (AF) is excluded from this recommendation.

OBJECTIVE

The goals of our study were to measure and describe anti-Xa levels of patients with a BMI ≥40 kg/m2 and/or a weight ≥120 kg with a clinical indication of AF or VTE who were treated with apixaban, and to determine whether BMI or weight are associated with anti-Xa levels in this population.

METHODS

We conducted an observational cohort study at a single health care system in Oregon, USA. Patients meeting enrollment criteria were recruited and had peak and trough apixaban anti-Xa levels drawn.

RESULTS

Of 55 patients enrolled, 5 (9%) had peak anti-Xa levels below the reference range and 3 (6%) had trough anti-Xa levels below the reference range. BMI did not significantly correlate with peak or trough anti-Xa levels (r = -0.10, p = 0.45 and r = -0.14, p = 0.31). Weight had a moderate, negative correlation with peak anti-Xa levels (r = -0.42, p = 0.002) and a weak, negative correlation with trough anti-Xa levels (r = -0.32, p = 0.02).

CONCLUSIONS AND RELEVANCE

This study provides evidence that anti-Xa levels among obese patients are not substantially different from patients with nomral BMI and weight. This supports recent ISTH guidance for standard dosing of apixaban for VTE patients with BMI >40 kg/m2 or weight >120 kg and provides additional evidence that the standard dosing may also be appropriate in patients with AF.

Multi-center retrospective study evaluating the efficacy and safety of apixaban versus warfarin for treatment of venous thromboembolism in patients with severe obesity

STUDY OBJECTIVE

Direct oral anticoagulants are the standard of care for venous thromboembolism (VTE) treatment. These agents are recommended regardless of patient weight and body mass index (BMI). However, there remains limited evidence supporting the use of apixaban in patients with severe obesity with a BMI ≥40 kg/m² or weight ≥120 kg. The purpose of this study was to evaluate the efficacy and safety of apixaban for VTE in patients with a BMI ≥40 kg/m² or weight ≥120 kg.

DESIGN

This multi-center, retrospective study compared the use of apixaban versus warfarin in patients with severe obesity for the treatment of VTE between January 1, 2012, and December 31, 2019. Patients were identified by diagnosis codes for acute VTE and a weight ≥120 kg or BMI ≥40 kg/m² . The primary efficacy outcome was time to recurrence of VTE within 12 months, and the primary safety outcome was time to major bleeding within 12 months. Secondary outcomes included incidence of recurrent VTE, major bleeding, clinically relevant non-major bleeding (CRNMB), all-cause mortality, number of total hospital encounters, and switch in anticoagulant.

MAIN RESULTS

A total of 1099 patients were included in the study. Of these, 314 patients received apixaban and 785 received warfarin. The mean weight and BMI were 137 kg and 46 kg/m² , respectively. Time to recurrent VTE was significantly longer in those treated with apixaban compared to warfarin (p = 0.018). After controlling for confounding factors, apixaban use was associated with a reduced risk of recurrent VTE compared to warfarin (hazard ratio [HR] = 0.54, 95% confidence interval [CI]: 0.29-0.97, p = 0.04). There were no significant differences in major bleeding, CRNMB, or all-cause mortality between groups.

CONCLUSION

In patients with a BMI ≥40 kg/m² or weight ≥120 kg, apixaban appears to be effective and safe for the treatment of VTE.