Management of rivaroxaban in relation to bodyweight and body mass index

Being precise with anticoagulation to reduce adverse drug reactions: are we there yet?

Anticoagulants are potent therapeutics widely used in medical and surgical settings, and the amount spent on anticoagulation is rising. Although warfarin remains a widely prescribed oral anticoagulant, prescriptions of direct oral anticoagulants (DOACs) have increased rapidly. Heparin-based parenteral anticoagulants include both unfractionated and low molecular weight heparins (LMWHs). In clinical practice, anticoagulants are generally well tolerated, although interindividual variability in response is apparent. This variability in anticoagulant response can lead to serious incident thrombosis, haemorrhage and off-target adverse reactions such as heparin-induced thrombocytopaenia (HIT). This review seeks to highlight the genetic, environmental and clinical factors associated with variability in anticoagulant response, and review the current evidence base for tailoring the drug, dose, and/or monitoring decisions to identified patient subgroups to improve anticoagulant safety. Areas that would benefit from further research are also identified. Validated variants in VKORC1, CYP2C9 and CYP4F2 constitute biomarkers for differential warfarin response and genotype-informed warfarin dosing has been shown to reduce adverse clinical events. Polymorphisms in CES1 appear relevant to dabigatran exposure but the genetic studies focusing on clinical outcomes such as bleeding are sparse. The influence of body weight on LMWH response merits further attention, as does the relationship between anti-Xa levels and clinical outcomes. Ultimately, safe and effective anticoagulation requires both a deeper parsing of factors contributing to variable response, and further prospective studies to determine optimal therapeutic strategies in identified higher risk subgroups.

Obesity Paradox: Fact or Fiction?

PURPOSE OF REVIEW

Obesity is related to several comorbidities such as type 2 diabetes mellitus, cardiovascular disease, heart failure, and various types of cancers. While the detrimental effect of obesity in both mortality and morbidity has been well established, the concept of the obesity paradox in specific chronic diseases remains a topic of continuous interest. In the present review, we examine the controversial issues around the obesity paradox in certain conditions such as cardiovascular disease, several types of cancer and chronic obstructive pulmonary disease, and the factors that may confound the relation between obesity and mortality.

RECENT FINDINGS

We refer to the obesity paradox when particular chronic diseases exhibit an interesting "paradoxical" protective association between the body mass index (BMI) and clinical outcomes. This association, however, may be driven by multiple factors among which the limitations of the BMI itself; the unintended weight loss precipitated by chronic illness; the various phenotypes of obesity, i.e., sarcopenic obesity or the athlete's obesity phenotype; and the cardiorespiratory fitness levels of the included patients. Recent evidence highlighted that previous cardioprotective medications, obesity duration, and smoking status seem to play a role in the obesity paradox. The obesity paradox has been described in a plethora of chronic diseases. It cannot be emphasized enough that the incomplete information received from a single BMI measurement may interfere with outcomes of studies arguing in favor of the obesity paradox. Thus, the development of carefully designed studies, unhampered by confounding factors, is of great importance.

Rivaroxaban Pharmacokinetics in Obese Subjects: A Systematic Review

INTRODUCTION

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality globally. The direct oral anticoagulants, including rivaroxaban, are relatively novel therapeutic options in the treatment and prevention of VTE. There is a conflicting and inconclusive evidence surrounding the pharmacokinetics (PK) of rivaroxaban in patients with VTE who are obese.

OBJECTIVES

We conducted a systematic review to provide an overview, and to synthesize the available evidence in the current literature pertaining to rivaroxaban PK in obese subjects who are healthy or diseased.

METHODS

The PubMed, Embase, ScienceDirect, Rayyan, and Cochrane Library databases were systematically searched from 1 May 2021 through 28 February 2022. Studies investigating rivaroxaban PK in adult obese subjects were included in the review. Pertinent data, including anthropometric parameters, rivaroxaban dosage regimen, PK parameters, PK model, and outcome measures were extracted. Reference values of rivaroxaban PK parameters in the general population were used for comparison purposes. The review protocol was registered in the PROSPERO database (CRD42020177770).

RESULTS

In the 11 studies included in this systematic review, over 7140 healthy or diseased subjects received rivaroxaban therapy, with varying clinical indications in the diseased population. The reported PK parameters of rivaroxaban in obese subjects compared with reference values in the general population were variable. The reported values of the volume of distribution (V_d) among obese subjects (73.4-82.8 L) fell within the range of values reported/calculated for the general population (59.4-104 L), assuming complete bioavailability. However, some of the reported values of clearance (CL) in obese subjects (7.86-16.8 L.h^-1) do not fall within the range of values reported/calculated for the general population (5.57-11.3 L.h^-1). The reported maximum plasma concentrations in obese subjects versus the general population following a 10 mg dose were 149 vs. 143-180 µg.L^-1, and following a 20 mg dose were 214-305 vs. 299-360 µg.L^-1, respectively. The area under the plasma concentration versus time curves (AUC) over different intervals in obese subjects versus the general population following a 10 mg dose were 1155 (AUC from time zero to infinity [AUC_∞]) vs. 1029 (AUC_∞) µg.h.L^-1; and 1204-2800 (AUC from time zero to 24 h [AUC₂₄]) vs. 3200 (AUC₂₄) µg.h.L^-1, respectively, following a 20 mg dose. The reported values of half-life and time to reach the maximum plasma concentration in obese subjects versus the general population were not consistent across studies.

CONCLUSION

Variable changes and inconsistencies in different rivaroxaban PK parameters were reported in obese subjects. Further well-designed studies are warranted to better characterize the PK and clinical outcomes of rivaroxaban in subjects with obesity.

Effectiveness and safety of rivaroxaban versus warfarin among nonvalvular atrial fibrillation patients with obesity and diabetes

AIMS

To compare clinical outcomes of rivaroxaban and warfarin in patients with nonvalvular atrial fibrillation (NVAF) and concurrent obesity and diabetes.

METHODS

Patients aged ≥18 years were identified from a healthcare claims database with the following criteria: newly initiating rivaroxaban or warfarin, ≥1 medical claim with a diagnosis of AF, obesity determined by validated machine learning algorithm, and ≥1 claim with a diagnosis of diabetes or for antidiabetic medication. Treatment cohorts were matched using propensity scores and were compared for stroke/systemic embolism (SE) and major bleeding using Cox proportional hazards models.

RESULTS

A total of 9999 matched pairs of NVAF patients with obesity and diabetes who initiated treatment with rivaroxaban or warfarin were included. The composite risk of stroke/SE was significantly lower in the rivaroxaban cohort compared with the warfarin cohort (HR 0.82; 95% CI 0.74-0.90). Risks of ischemic and hemorrhagic strokes were also significantly reduced with rivaroxaban versus warfarin, but not SE. Major bleeding risk was similar between treatment cohorts (HR 0.92; 95% CI 0.78-1.09).

CONCLUSIONS

In NVAF patients with comorbidities of obesity and diabetes, rivaroxaban was associated with lower risks of stroke/SE and similar risk of major bleeding versus warfarin.

Body Mass Index Influence on the Clinical Outcomes for Nonvalvular Atrial Fibrillation Patients Admitted to a Hospital Treated with Direct Oral Anticoagulants: A Retrospective Cohort Study

BACKGROUND

Considering that the current fixed dose of direct oral anticoagulants (DOACs) might have insufficient anticoagulation effect for overweight patients, the aim of this study was to compare the effectiveness and safety of anticoagulation between dabigatran and rivaroxaban in different body mass index (BMI) population.

METHODS

We conducted a retrospective cohort study of 2402 DOAC anticoagulated patients with atrial fibrillation who underwent catheter ablation (1290 dabigatran, 53.7% and 1112 rivaroxaban, 46.3%) between January 2017 and December 2018. Patients were distributed based on the BMI into nonobese (1362, BMI <25 kg/m2), preobese (521, BMI 25.0-29.9 kg/m2), class I obese (344, BMI 30.0-34.9 kg/m2) and class II+ obese (175, BMI ≥35.0 kg/m2). We collected information regarding clinical features, laboratory data, bleeding complications and systemic embolic events from the electrical medical records system during 12 months.

RESULTS

The incidence of systemic embolism and stroke complications was higher in the class II+ obese group (P=0.001 and P=0.003). The incidence of bleeding complications and the levels of anticoagulation parameters under the bleeding threshold were similar among the four groups (P>0.05). Cumulative Kaplan-Meier analysis illustrated that rivaroxaban-treated patients who belonged to higher BMI subgroups were more likely to experience shorter time to thrombosis (TTT) (12-month TTT rates of 0.5% for nonobese vs 1.7% for class I obese patients, HR=3.716, P=0.005; 12-month TTT rates of 0.5%, for nonobese vs 4.0% for class II+ obese patients, HR=6.843, P=0.001). However, no statistical significant difference in terms of the time to bleeding complications and the time to cumulative events among the four groups was observed. By multivariate analysis, a higher BMI value (BMI ≥25 kg/m2) (P=0.019; OR=2.094, 95%CI: 1.129-3.883) was an independent predictor for thrombosis in patients treated with dabigatran or rivaroxaban. Positive linear relationship was observed between BMI levels and occurrence rate of thrombosis and bleeding in under anticoagulation patients with NVAF (R2=0.451 and R2=0.383, respectively).

CONCLUSION

The fixed dose of 15 mg rivaroxaban might carry a risk of under exposure, which would lead to an increase of thromboembolic complications in patients with high BMI. Therefore, rivaroxaban dose increase was suggested for obese patients. Use of DOACs appears to have considerable safety in obese patients.

Safety and efficacy of direct oral anticoagulants across body mass index groups in patients with venous thromboembolism: a retrospective cohort design

Current literature on the safety and efficacy of direct oral anticoagulants (DOACs) in patients of extreme weights are limited, however, they are still being prescribed in these populations. The objective of this study is to describe the safety and efficacy of DOAC therapy in patients of extreme weights for the treatment of venous thromboembolism (VTE) using body mass index (BMI) groups. A multi-site, retrospective cohort design at four hospitals was performed. Patients who experienced an initial VTE between November 2012 and August 2017 and placed on a DOAC were included. Patients were defined as: extremely obese (EO) if BMI ≥ 40 kg/m², obese if BMI 30-39.9 kg/m², normal/overweight if BMI 18.5-29.9 kg/m², and underweight if BMI < 18.5 kg/m². The primary efficacy outcome of recurrent VTE and primary safety outcome of major bleeding (MB) within 12 months were compared between weights. Univariate statistical tests and multivariate logistic regression analyses were performed. Rates of recurrent VTE showed no significant differences (p = 0.58) across groups; 7.8% (11/142) EO, 4.7% (18/383) obese, 5.2% (27/517) normal/overweight, and 5.9% (1/17) underweight. Proportions of MB were overall significantly different (p = 0.026); 6.3% (9/142) EO, 10.4% (40/383) obese, 10.1% (52/517) normal/overweight, and 29.4% (5/17) underweight. EO and obese patients had similar odds of MB compared to normal/overweight (OR 0.61, 95% CI [0.29, 1.26] and OR 1.04, 95% CI [0.67, 1.61]). Underweight patients showed larger odds of MB compared to normal/overweight (OR 3.73, 95% CI [1.26, 11.0]). This study found that recurrence of VTE was not associated with BMI. However, the proportions of major bleeding were statistically different among the BMI categories.

Investigation of Direct-Acting Oral Anticoagulants and the Incidence of Venous Thromboembolism in Patients Weighing ≥120 kg Compared to Patients Weighing <120 kg

Background:

Direct oral anticoagulants (DOACs) present a favorable alternative to warfarin based on the decreased burden of monitoring and fewer drug and food interactions. Although studied in the general population, limited clinical data justifying efficacy in patients weighing ≥120 kg present concern for using DOACs in this specific population.

Objective:

The purpose was to identify if a difference exists in incidence of recurrent thromboembolic events in patients receiving a DOAC for the indication of venous thromboembolism (VTE) weighing ≥120 kg compared to patients weighing <120 kg.

Methods:

A retrospective database analysis was conducted with patients on apixaban, dabigatran, or rivaroxaban for treatment of VTE from the Veterans Integrated Service Network 8 between January 2012 and June 2017. The primary outcome was incidence of recurrent VTEs while on anticoagulation. Fisher’s exact tests were used to evaluate difference in VTEs between the groups.

Results:

There were 133 patients weighing ≥120 kg and 1063 patients weighing <120 kg identified within the 5-year time frame that met inclusion criteria. Although no statistically significant difference was found in incidence of recurrent VTEs between study groups (0.8% vs 1.1%; odds ratio: 0.66; 95% confidence interval: 0.09-5.14; P = .69) few events occurred limiting the power to be able to detect a difference.

Conclusion:

This study found no difference in VTE recurrence in patients weighing ≥120 kg compared to patients <120 kg with few events in either group. Although promising, additional studies are needed to confirm these findings.

Morbidly Obese Patient on Rivaroxaban Presents With Recurrent Upper Extremity Deep Vein Thrombosis: A Case Report

A morbidly obese patient with history of deep vein thrombosis and pulmonary embolism was diagnosed with an acute left upper extremity deep vein thrombosis and started on rivaroxaban. Three months later, the patient returned with swelling in the right arm and was found to have a right brachial thrombosis. Anticoagulant therapy was switched to a low-molecular-weight heparin, and patient was discharged on enoxaparin along with an order to follow-up with a hematologist. Subanalyses from randomized controlled trials, pharmacokinetic/pharmacodynamic, and real-world studies suggest that rivaroxaban may be effective and safe in morbidly obese patients for primary and secondary prevention of venous thromboembolism. However, the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis does not recommend the use of direct-acting oral anticoagulants in this population. If used, drug levels should be monitored to guide the therapy. Due to the disparity in data to show efficacy and safety of rivaroxaban in morbidly obese subjects, the interpatient variability of rivaroxaban’s effects in subjects, and the lack of defined therapeutic range for rivaroxaban drug concentration, rivaroxaban should be used cautiously in this population.

Comparing the Efficacy and Safety of Direct Oral Anticoagulants With Warfarin in the Morbidly Obese Population With Atrial Fibrillation

BACKGROUND

The International Society of Thrombosis and Haemostasis recommends avoiding direct oral anticoagulants (DOACs) in morbidly obese patients with a body mass index (BMI) >40 kg/m² or weight >120 kg because of limited clinical data in this group of patients.

OBJECTIVES

The objective of this study was to evaluate the efficacy and safety of DOACs in morbidly obese patients with atrial fibrillation or flutter.

METHODS

A retrospective, single-center cohort study was conducted of patients older than 18 years, with BMI >40 kg/m² or weight >120 kg, who were diagnosed as having atrial fibrillation or flutter and who received warfarin or DOACs (ie, dabigatran, rivaroxaban, or apixaban). The primary efficacy outcome was the incidence of ischemic stroke or transient ischemic attack (TIA), whereas the primary safety outcome was the incidence of major bleeding.

RESULTS

A total of 64 patients in each group were included in the study analysis. The incidence rate of ischemic stroke or TIA was 1.75%/year in the DOAC group compared with 2.07%/year in the warfarin group (rate ratio = 0.84; 95% CI = 0.23 to 3.14; P = 0.80). The incidence rate of major bleeding was 2.18%/year in the DOAC group, compared with 4.97%/year in the warfarin group (rate ratio = 0.44; 95% CI = 0.15 to 1.25; P = 0.11). Conclusion and Relevance: Apixaban and rivaroxaban may be considered as alternatives to warfarin for atrial fibrillation or flutter in morbidly obese patients. Dabigatran use in morbidly obese patients needs caution until further studies are conducted.

Use of direct oral anticoagulants in antiphospholipid syndrome

The direct oral anticoagulants (DOACs) are therapeutic alternatives to warfarin and other vitamin K antagonists (VKAs), and constitute the standard of care for many indications. VKAs constitute the conventional therapy for the treatment and secondary thromboprophylaxis of thrombotic antiphospholipid syndrome (APS), but are often problematic, owing to the variable sensitivity of thromboplastins to lupus anticoagulant. Thus, the International Normalized Ratio may not accurately reflect anticoagulation intensity, or be clinically effective. Definition of the current role of DOACs in the treatment of APS is based on limited clinical trial data and information from other sources, including manufacturers' data, case series or cohort studies, and expert consensus. The Rivaroxaban in Antiphospholipid Syndrome (RAPS) randomized controlled trial (RCT), which had a laboratory surrogate primary outcome measure, suggests that rivaroxaban has the potential to be an effective and convenient alternative to warfarin in thrombotic APS patients with a single venous thromboembolism event requiring standard-intensity anticoagulation. However, further studies, in particular to provide better long-term efficacy and safety data, are needed before it can be widely recommended. APS patients are clinically heterogeneous, with the risk of recurrent thrombosis and the intensity of anticoagulation being influenced by their clinical phenotype and risk profile. DOAC trials involving homogeneous thrombotic APS populations, with the antiphospholipid antibody status well defined, will help to optimize the appropriate treatment in APS patient subgroups. Ongoing and emerging DOAC RCTs should provide further information to guide the use of DOACs in APS patients. Optimal identification of APS patients is a key step in working towards improved therapeutic strategies in these individuals.