Effectiveness and safety of apixaban and rivaroxaban for acute venous thromboembolism therapy in patients with extremes in bodyweight

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.

Efficacy and safety of factor Xa inhibitors in low body weight patients

STUDY OBJECTIVE

The purpose of this study is to provide evidence for the safety and efficacy of factor Xa inhibitors in patients with a weight ≤60 kg or BMI < 18.5 kg/m2 .

DESIGN

Multicenter, retrospective, cohort study.

SETTING

Twenty-two Ascension Health hospitals.

PATIENTS

Low-body-weight adult patients (weight ≤ 60 kg or BMI < 18.5 kg/m2 ) receiving treatment for atrial fibrillation or venous thromboembolism.

INTERVENTION

Factor Xa inhibitors (apixaban or rivaroxaban) or warfarin.

MEASUREMENTS AND MAIN RESULTS

This study included 2538 patients between the factor Xa inhibitors (n = 1695) and warfarin (n = 843) groups with a mean weight of 53.5 ± 5.5 kg and BMI of 20.7 ± 3.1 kg/m2 . No significant difference in time to major bleeding was noted after controlling for potential confounders (HR 1.03, 95% CI 0.70-1.53, p = 0.87); similar results were seen following propensity score matching. Thromboembolism (5.3% vs. 6.2%, p = 0.38), composite major + clinically relevant nonmajor bleeding (9.8% vs. 11.5%, p = 0.18), and all-cause mortality (10.7% vs. 12.8%, p = 0.12) were similar between patients receiving factor Xa inhibitors versus warfarin.

CONCLUSION

No differences in safety or effectiveness were noted between factor Xa inhibitors versus warfarin. These findings provide encouraging evidence to support the use of factor Xa inhibitors in low-body-weight patients.

Examining an Interaction Between Plasma Exchange and Apixaban Resulting in an Acute Ischemic Stroke

Objective: Therapeutic drug monitoring is not routinely considered necessary in patients undergoing plasma exchange; however, it is possible for serum concentrations of select medications to be impacted by this procedure. Case: We describe a 50-year-old patient who presented to our facility with new onset aphasia and right-sided weakness. Despite presenting with a National Institute of Health Stroke Severity (NIHSS) score of 23, the patient did not receive fibrinolytic therapy due to his being anticoagulated with apixaban for atrial fibrillation. The patient instead underwent an emergent thrombectomy which resulted in a post-operative Thrombolysis in Cerebral Infarction (TICI) score of 3. The patient had a significant past medical history including numerous previous strokes necessitating assistance with activities of daily living, atrial fibrillation, chronic kidney disease, and thrombocytopenic purpura, for which he was receiving twice weekly plasma exchange and immunomodulatory therapy. The patient's last plasma exchange session was approximately 24 hours prior to admission, leading us to hypothesize that the patient's plasma exchange may have been implicated in the removal of apixaban from the serum and precipitating a stroke. Discussion/Conclusions: Heterogeneity of data exists when evaluating the effect of plasma exchange on apixaban. Although the drug properties of apixaban, including its low volume of distribution and high plasma protein binding capacity, support the notion that it may be vulnerable to removal through plasma exchange, only one other case report has been published on this phenomenon.

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.

DOAC compared with warfarin for VTE in patients with obesity: a retrospective cohort study conducted through the VENUS network

The effectiveness and safety of direct oral anticoagulants (DOAC) compared with warfarin remains uncertain in obese patients. We assessed the comparative effectiveness and safety of DOACs with warfarin for the treatment of VTE among obese patients. This multi-center retrospective cohort study included adults with a BMI ≥ 35 kg/m2 or weight ≥ 120 kg prescribed either DOAC (apixaban, dabigatran, edoxaban, rivaroxaban) or warfarin for a VTE diagnosis. The primary outcome was the 12-month rate of recurrent VTE. The secondary outcome was the 12-month rate of major bleeding. Among 5626 patients, 67% were prescribed warfarin and 33% were prescribed a DOAC. The 12-month VTE recurrence rate was 3.6% (67/1823) for patients treated with DOAC compared with 3.8% (143/3664) for patients treated with warfarin [odds ratio for recurrent VTE on warfarin versus DOAC (OR) (95% CI).07 (0.80, 1.45)]. The 12-month major bleeding rate was 0.5% (10/1868) for patients on DOAC versus 2.4% (89/3758) on warfarin [OR 4.25 (2.19, 8.22)]. Similar proportions of recurrent VTE occurred across BMI thresholds on DOAC and warfarin: for BMI ≥ 35 kg/m2 (N = 5412), 3.6% versus 3.8%, respectively [OR 1.08 (0.80, 1.46)]; for BMI ≥ 40 kg/m2 (N = 2321), 4.4% versus 3.5%, respectively [OR 0.80 (0.51, 1.26)]; and for BMI ≥ 50 kg/m2 (N = 560), 3.1% versus 3.7%, respectively [OR 1.18 (0.39, 3.56)]. Similar proportions of recurrent VTE occurred in patients with obesity treated for VTE with DOACs and warfarin. DOACs were associated with lower major bleeding compared to warfarin in patients with obesity and VTE.

Pharmacist Practice Patterns Regarding Direct Oral Anticoagulants for Treatment of Venous Thromboembolism

Background: Direct oral anticoagulants (DOACs) are increasingly prescribed for the treatment of venous thromboembolism (VTE). However, little is known regarding pharmacists' practice patterns and preferences in clinical areas of contention, such as initiation dosing, obesity, and renal impairment. Objective: To determine pharmacist trends in practice regarding DOACs for the treatment of VTE overall and within areas of clinical controversy. Methods: An electronic survey was distributed to pharmacists in the United States through national and state pharmacy organizations. Responses were collected for 30 days. Results: One hundred fifty-three complete responses were submitted. The majority of pharmacists preferred apixaban (90.2%) for the oral treatment of venous thromboembolism. When initiating apixaban or rivaroxaban for a new VTE, 76% and 64% of pharmacists surveyed, respectively, state the duration of the initiation dose phases are reduced if the patient received parenteral anticoagulation. Fifty-eight percent of pharmacists used body mass index to evaluate the appropriateness of DOACs in obese patients whereas 42% used total body weight. Preference for rivaroxaban (31.4%) was higher in this population compared to the global population (10%). Apixaban was preferred for patients with renal impairment (92.2%). However, as creatinine clearance as calculated by the Cockcroft-Gault equation (CrCl) reduced to ≤15 milliliters/minute (mL/min), preference for warfarin increased (36%). Conclusion: This national survey of pharmacists demonstrated an overall preference for apixaban and significant variability in practice patterns regarding DOACs for patients with new VTE, patients with obesity, and patients with renal impairment. Further research is warranted to evaluate the efficacy and safety of DOAC initiation dosing phase modifications. Prospective evaluations of DOACs in obese and renal dysfunction populations would confirm the safety and efficacy of DOACs in these populations.

Evaluation of safety and efficacy outcomes of direct oral anticoagulants versus warfarin in normal and extreme body weights for the treatment of atrial fibrillation or venous thromboembolism

Despite evolving evidence, the use of direct oral anticoagulants (DOACs) in patients with extremes of body weight remains controversial. This study aimed to measure the impact of DOACs compared to warfarin on safety and efficacy outcomes in extreme body weight patients. This multi-center, health system, retrospective study examined the outcomes of patients with all body weights and extreme body weights prescribed a DOAC (rivaroxaban, apixaban, dabigatran, edoxaban) or warfarin for atrial fibrillation or venous thromboembolism over a 9-year period. The primary outcome was a composite of thromboembolism, symptomatic recurrent VTE, or severe bleeding; analyzed by pre-determined BMI cutoffs. A total of 19,697 patients were included in the study: 11,604 in the DOAC group and in the 8093 in the warfarin group. 295 patients were underweight and 9108 patients were pre-obese to obese class 3. After adjusting for potential confounders, warfarin patients had higher odds of experiencing the composite outcome compared to DOAC patients (OR 1.337, 95% CI 1.212-1.475). Additionally, obese patients were 24.6% more likely to experience the outcome compared to normal BMI patients. Adjusted modeling showed that warfarin patients experienced higher bleed rates compared to DOAC patients (OR 1.432, 95% CI 1.266-1.620). Obese patients were less likely to be diagnosed with a bleed (OR 0.749, 95% CI 0.658-0.854), and underweight patients were more likely to be diagnosed with a bleed (OR 1.522, 95% CI 1.095-2.115) compared to normal BMI patients. In conclusion, DOACs for atrial fibrillation or VTE in patients with extreme body weights appear safe and effective when compared to warfarin.

Effectiveness, safety, and healthcare costs associated with rivaroxaban versus warfarin among venous thromboembolism patients with obesity: a real-world study in the United States

Prior observational studies suggest rivaroxaban is safe and effective among patients with morbid obesity who suffered a venous thromboembolism (VTE) event, but existing data are more limited in the broader population of VTE patients with obesity. This study assessed VTE recurrence, major bleeding, healthcare resource utilization, and healthcare costs among VTE patients with obesity who received rivaroxaban versus warfarin. VTE patients with obesity who initiated rivaroxaban or warfarin after a first VTE (index date) were identified from the IQVIA PharMetrics® Plus database (01/02/2011–09/30/2019). The follow-up period spanned from the index date until health plan disenrollment, end of data availability, cancer diagnosis/treatment, end of the 12 month post-index period, or (for the analysis of major bleeding) anticoagulant discontinuation or switch. Patient characteristics were balanced using inverse probability of treatment weighting. The weighted rivaroxaban (N = 8666) and warfarin cohorts (N = 5946) were well balanced (mean age = 51 years, females = 52%). Over a 9.6 months mean observation period, rivaroxaban users had a significantly lower risk of VTE recurrence [7.0% vs. 8.2%, HR(95% CI) = 0.85(0.75;0.97)] and a similar risk of major bleeding [4.1% vs. 3.6%, HR(95% CI) = 1.11(0.89;1.37)] relative to warfarin users at 12 months. Relative to warfarin users, rivaroxaban users had significantly fewer all-cause outpatient visits [RR(95% CI) = 0.71(0.70;0.74)]. The higher pharmacy costs incurred by rivaroxaban recipients (cost difference = $1252) were offset by lower medical costs (cost difference = − $2515, all p < 0.05) compared with warfarin recipients. Our findings suggest that rivaroxaban is safe and effective versus warfarin, and associated with lower medical costs among VTE patients with obesity.

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.

Rivaroxaban in acute venous thromboembolism: UK prescribing experience

BACKGROUND

Rivaroxaban was reported as effective as traditional therapies for the acute treatment of venous thromboembolism (VTE) with fewer major bleeding complications in the seminal Einstein program and is now a recommended option for the treatment of VTE around the world.

OBJECTIVE

To report the safety and efficacy of rivaroxaban in daily care for the management of acute VTE in the United Kingdom.

PATIENTS/METHOD

The FIRST registry is a UK-only, multicenter, noninterventional, observational VTE study (NCT02248610). Consecutive patients diagnosed with acute VTE, managed with rivaroxaban, were recruited and followed for up to 5 years. The primary outcomes were treatment-emergent symptomatic objectively diagnosed recurrent VTE, major and clinically relevant nonmajor bleeding (CRNMB), and all-cause mortality.

RESULTS

A total of 1262 participants were recruited between 2014 and 2018. Participants were heterogeneous, with age range 18 to 95 years, weight 35 to 234 kg, and maximum body mass index 64.4 kg/m2. The median duration of treatment exposure was 135 days (interquartile range [IQR], 84-307) and overall follow-up 497 days (IQR, 175-991). There were seven episodes of symptomatic VTE recurrence, 0.6%, (0.74/100 patient-years; 95% confidence interval [CI], 0.19-1.28). There were 79 of 1239 (6.4%), 8.66 of 100 patient-years (95% CI, 6.90-10.73) first episodes of major or CRNMB, which were most frequently reported by women aged <50 years as abnormal vaginal bleeding.

CONCLUSIONS

Rivaroxaban is an effective and safe single drug modality for the treatment of VTE in daily practice in the United Kingdom. Data to determine the optimal anticoagulation therapy for women of childbearing age are needed.

Oral anticoagulant use in patients with morbid obesity: A systematic review and meta-analysis

OBJECTIVES

Obesity is associated with increased risks of atrial fibrillation (AF) and venous thromboembolism (VTE) for which anticoagulation is commonly used. However, data on the efficacy and safety of oral anticoagulants in patients with morbid obesity are limited.

METHODS

We conducted a systematic review and meta-analysis to evaluate the efficacy and safety of direct oral anticoagulants (DOACs) or vitamin K antagonists (VKAs) for AF or VTE in patients with morbid obesity.

RESULTS

We included 3 randomized controlled trials (5 studies) and 18 observational studies in adult patients with a body weight ≥ 120 kg, body mass index (BMI) ≥ 40 kg/m2 or classified as morbid obesity who received DOACs or VKAs for AF or VTE (N=77,687). The primary efficacy outcome was stroke/systemic embolism or recurrent VTE, and the primary safety outcome was major bleeding. DOACs were associated with a pooled incidence rate of stroke/systemic embolism of 1.16 per 100 person-years, compared to 1.18 with VKAs. The incidence of recurrent VTE on DOACs was 3.83 per 100 person-years, compared to 6.81 on VKAs. In both VTE and AF populations, DOACs were associated with lower risks of major bleeding compared to VKAs. However, all observational studies had moderate to serious risks of bias.

CONCLUSIONS

Patients with morbid obesity on DOACs had similar risks of stroke/systemic embolism, lower rates of recurrent VTE and major bleeding events compared to those on VKAs. However, the certainty of evidence was low given that studies were mostly observational with high risk of confounding.

Use of direct oral anticoagulants in patients with obesity for treatment and prevention of venous thromboembolism: Updated communication from the ISTH SSC Subcommittee on Control of Anticoagulation

Although direct-acting oral anticoagulants (DOACs) have widespread first-line use for treatment and prevention of venous thromboembolism (VTE), uncertainty remains regarding their efficacy and safety in patients with obesity. We reviewed available data for use of DOACs for VTE treatment and prevention in patients with obesity, including phase 3, phase 4, meta-analyses, and pharmacokinetic and pharmacodynamics studies. In addition, we reviewed available data regarding DOACs in bariatric surgery. We provide updated guidance recommendations on using DOACs in patients with obesity for treatment and prevention of VTE, as well as following bariatric surgery.

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

Introduction

As a result of limited clinical data, guidelines do not recommend the use of non-vitamin K antagonist oral anticoagulants in patients who weigh > 120 kg or have a body mass index (BMI) > 40 kg/m².

Methods

This post hoc analysis of the AMPLIFY trial evaluated the efficacy (venous thromboembolism [VTE]/VTE-related death), safety (major and composite of major and clinically relevant non-major [CRNM] bleeding), and exposure of apixaban compared with enoxaparin followed by warfarin for the treatment of VTE by body weight (≤ 60, > 60 to < 100, ≥ 100 to < 120, ≥ 120 kg) and BMI (≤ 25, > 25 to 30, > 30 to 35, > 35 to 40, > 40 kg/m²).

Results

Among the AMPLIFY safety population, 5384 and 5359 patients had recorded body weight (range 28.9 to 222.0 kg; ≥ 120 kg, n = 290) and BMI (range 12.5–71.8 kg/m²; > 40 kg/m², n = 263), respectively. The rates of recurrent VTE/VTE-related death for apixaban versus enoxaparin/warfarin were similar across body weight subgroups: relative risks (RR; 95% confidence intervals [CI]) were 0.63 (0.23, 1.72), 0.99 (0.65, 1.50), 0.77 (0.34, 1.72), and 0.20 (0.02, 1.72) for the ≤ 60, > 60 to < 100, ≥ 100 to < 120, and ≥ 120 kg groups, respectively (P_interaction = 0.44). The rates of major bleeding were lower with apixaban versus enoxaparin/warfarin; RRs (95% CI) were 0.15 (0.02, 1.15), 0.41 (0.21, 0.77), not estimable, and 0.34 (0.04, 3.22), respectively (P_interaction = not estimable). The rates of major/CRNM bleeding were significantly lower for apixaban versus enoxaparin/warfarin; RRs (95% CI) were 0.46 (0.24, 0.89), 0.49 (0.38, 0.63), 0.30 (0.16, 0.58), and 0.28 (0.12, 0.66), respectively (P_interaction = 0.36). Similar trends were seen in the BMI subgroups. There was a modest, not clinically meaningful, decrease (< 30%) in the median predicted exposure with increasing body weight (n = 281).

Conclusions

The findings of this post hoc analysis support the use of apixaban in patients with body weight ≥ 120 kg or BMI > 40 kg/m².

Trial Registration Number

NCT00643201

Graphic Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01716-8.

Direct Oral Anticoagulants in the Treatment of Venous Thromboembolism: Use in Patients with Advanced Renal Impairment, Obesity, or Other Weight-Related Special Populations

There are currently more than 7 million patients taking a direct oral anticoagulant (DOAC), with more new prescriptions per year than warfarin. Despite impressive efficacy and safety data for the treatment of venous thromboembolism, patients with obesity or advanced renal impairment represented a small portion of the patients enrolled in the phase 3 clinical trials. Therefore, to evaluate the potential use of DOACs in these special populations, clinicians need to have an understanding of the pharmacokinetics and pharmacodynamics of these agents in these settings. Since data from randomized controlled trials are limited, data from observational trials are helpful in gaining comfort with the use of DOACs in these special populations. Selecting the appropriate dose for each agent is imperative in achieving optimal patient outcomes. We provide an extensive review of the pharmacokinetics, pharmacodynamics, phase 3 clinical trials, and observational studies on the use of DOACs in patients with advanced renal impairment, obesity, or other weight-related special populations to provide clinicians with a comprehensive understanding of the data for optimal drug and dose selection.

Effectiveness and Safety of Apixaban vs. Warfarin in Venous Thromboembolism Patients with Obesity and Morbid Obesity

This study integrated 5 United States healthcare claims databases to evaluate the risk of recurrent venous thromboembolism (VTE) and major bleeding (MB) among VTE patients who initiated apixaban vs. warfarin, stratified by obesity. Obese and morbidly obese patients were identified based on diagnosis codes. Stabilized inverse probability treatment weighting (IPTW) was conducted to balance observed patient characteristics between treatment cohorts. An interaction analysis was conducted to evaluate treatment effects of apixaban vs. warfarin according to obesity status. Cox proportional hazard models were used to evaluate the risk of recurrent VTE and MB among IPTW weighted obese and morbidly obese patients. A total of 112,024 non-obese patients and 43,095 obese patients were identified, of whom 19,751 were morbidly obese. When stratified by obesity status post-IPTW, no significant interactions were observed for effects of apixaban vs. warfarin on recurrent VTE or MB (interaction p > 0.10). Among IPTW obese and morbidly obese patients, apixaban was associated with a significantly lower risk of recurrent VTE (obese: 0.73 [0.64–0.84]; morbidly obese: 0.65 [0.53–0.80]) and MB (obese: 0.73 [0.62–0.85]; morbidly obese: 0.68 [0.54–0.86]) as compared with warfarin. In this large sample of obese and morbidly obese VTE patients, apixaban had a significantly lower risk of recurrent VTE and MB vs. warfarin.