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

Factor Xa Inhibitors versus warfarin in patients with morbid obesity and atrial fibrillation

PURPOSE

Factor Xa Inhibitors have emerged as a first-line agent in the management of non-valvular atrial fibrillation (NVAF), but there is a need for additional data surrounding their use in the morbidly obese population. The purpose of this study was to evaluate whether Factor Xa Inhibitors are as safe and effective as warfarin for the treatment of NVAF in individuals with a BMI ≥ 40 kg/m2 and/or weight ≥ 120 kg.

METHODS

This was a multi-center retrospective cohort study comparing the use of Factor Xa Inhibitors (apixaban and rivaroxaban) to warfarin for the management of NVAF in adult patients with a BMI ≥ 40 kg/m2 and/or weight ≥ 120 kg. The primary outcomes were stroke or systemic embolism and major bleeding within 12 months.

RESULTS

A total of 3,156 patients were included in the final analysis; 1,396 in the warfarin group and 1760 in the Factor Xa Inhibitor group. The mean weight and BMI of the overall cohort was 134.1 kg and 44.7 kg/m2, respectively. There was no difference in stroke or systemic embolism (OR 1.21, 95% CI 0.78-1.85) or major bleeding (OR 0.99, 95% CI 0.65 - 1.53) with Factor Xa Inhibitors compared to warfarin after controlling for covariates.

CONCLUSION

This analysis of real-world data suggests no difference in bleeding or thrombotic outcomes for severely obese patients with NVAF taking Factor Xa Inhibitors compared to warfarin. Overall, our study adds further data to support the use of Factor Xa Inhibitors as an alternative to warfarin in severely obese patients with NVAF.

Comparing the Clinical Outcomes Observed with Rivaroxaban Versus Warfarin for the Management of Obese Patients with Non-valvular Atrial Fibrillation: a Systematic Review and Meta-analysis

BACKGROUND

Atrial fibrillation (AF) is an irregular heart rhythm which is becoming more and more common in this new era. Obesity is a risk factor for cardiovascular events, and obese patients are more at risk for stroke. The Framingham Heart Study demonstrated an increase in the developmental risk of AF by 4% for every unit (kg/m2) increase in body mass index (BMI). An anticoagulant is often required for the management of such patients. In this analysis, we aimed to systematically compare the clinical outcomes which were associated with rivaroxaban versus warfarin for the treatment of obese patients with non-valvular AF.

METHODS

PubMed, EMBASE, Web of Science, http://www.

CLINICALTRIALS

gov , Google Scholar, and Cochrane Central were the searched databases. Clinical outcomes including stroke, systemic embolism, and major bleeding were the endpoints. In this study, dichotomous data were analyzed by the RevMan software version 5.4. Risk ratio (RR) with 95% confidence interval (CI) was used for result interpretation.

RESULTS

Ten studies consisting of a total number of 168,081 obese participants were included whereby 81,332 participants were treated with rivaroxaban and 86,749 participants were treated with warfarin. The risks of ischemic (RR: 0.79, 95% CI: 0.74-0.84; P = 0.00001) and hemorrhagic stroke (RR: 0.61, 95% CI: 0.48-0.76; P = 0.0001) as well as systemic embolism (RR: 0.73, 95% CI: 0.62-0.87; P = 0.0004) were significantly lower with rivaroxaban compared to warfarin for the management of these obese patients with non-valvular AF. Rivaroxaban was also associated with a significantly lower risk of major bleeding (RR: 0.75, 95% CI: 0.65-0.87; P = 0.0001).

CONCLUSION

Based on this analysis, rivaroxaban seemed to be a better option in comparison to warfarin, due to its association with significantly lower risks of stroke and bleeding outcomes in obese patients with non-valvular AF. However, this hypothesis should further be confirmed in larger clinical trials.

The safety and efficacy of nonvitamin K antagonist oral anticoagulants in morbidly obese patients with atrial fibrillation: a meta-analysis

BACKGROUND AND AIM

Atrial fibrillation (AF) is the most frequently observed cardiac arrhythmia in clinical settings. Obesity can influence the efficacy of the treatment administered, which requires a larger dose and more time to accomplish therapeutic targets due to altered pathophysiology. Our study aimed to assess the overall efficacy and safety of nonvitamin K antagonist oral anticoagulants (NOACs) versus warfarin in AF patients with morbid obesity (BMI > 40 kg/m2 and/or weight > 120 kg) to prevent complications.

METHODS

We conducted a literature search on PubMed, Web of Science, the Cochrane Library, and Scopus till October 2022 for articles addressing the efficacy and safety of NOACs versus warfarin for the treatment of AF in morbidly obese patients. We performed the meta-analysis with RevMan software version 5.4 and Open Meta Analyst. The main outcomes assessed were stroke, major bleeding, and minor bleeding after anticoagulation, as did the history of comorbidities and risk factors in morbidly obese patients. Quality assessment was performed using Cochrane's ROB-2 tool and the Newcastle-Ottawa scale.

RESULTS

Regarding major bleeding events, pooled data showed that patients taking NOACs had a significantly lower risk than patients taking warfarin (OR = 0.54, 95% CI: [0.41-0.70]; p < 0.00001). However, for minor bleeding, there was a nonsignificant effect of NOACs on reducing the risk of bleeding (OR = 0.72, 95% CI = 0.47-1.09; p = 0.12), which became highly significant in favor of NOACs after sensitivity analysis (OR = 0.55, 95% CI = 0.49-0.61]; p < 0.00001). There was a significant difference in the incidence of stroke between the NOAC group and the warfarin group (OR = 0.69, 95% CI = 0.60-0.80]; p < 0.00001). According to the results of the single-arm study analysis, the overall effect of all the outcomes was associated with a high risk of disease development in patients receiving NOACs.

CONCLUSION

Our meta-analysis showed a favorable effect of NOACs vs warfarin in morbidly obese patients. Some outcomes were not significantly different, which calls for future research to better assess their safety and efficacy in this particular weight group.

TRIAL REGISTRATION

The study was registered with PROSPERO under registration number CRD42022362493 on October 2022.

Comparing Safety and Efficacy of Direct Oral Anticoagulants Versus Warfarin in Extreme Obesity

Background: Limited clinical data exists regarding use of direct oral anticoagulants (DOACs) in extreme obesity, specifically those ≥140 kg or having a body mass index (BMI) ≥ 50 kg/m2. Objective: Evaluate the safety and efficacy of DOACs in extreme obesity. Patients/Methods: A retrospective chart review was performed at a single center of patients aged 18-89 years and weight ≥140 kg or BMI ≥50 kg/m2 receiving warfarin or DOAC therapy. Patients were followed for 1 year from prescribing/study inclusion. The primary outcome was the difference in rates of any bleed (composite of major, nonmajor clinically relevant, or minor bleeding events as defined by International Society of Thrombosis and Haemostasis (ISTH) criteria) between groups. Secondary outcomes included individual components of the composite primary outcome and effectiveness in preventing thrombotic events within 12 months. Post-hoc multivariate analysis evaluated potential predictors of bleeding events within overall patient population. Results: Two-hundred eighty-five patients were included, 80 and 205 in the DOAC and warfarin groups, respectively. Rates of any documented bleeding event were comparable in DOAC and warfarin groups (17.5% vs 17.1%, P > .05). No significant difference in rates of minor (P = .067), nonmajor clinically relevant (P = .825), and major (P = 1) bleeding events were observed. Two thrombotic events occurred in the warfarin group compared to none in the DOAC group. Increasing weight was associated with bleeding events in multivariate analysis. Conclusions: This data did not demonstrate a difference in safety or efficacy outcomes between DOACs and warfarin when utilized in patients with extreme obesity.

Trends in prescribing and outcomes in obese versus non-obese patients receiving rivaroxaban therapy: an observational study using real-world data

PURPOSE

To investigate real-world prescribing trends and clinical outcomes based on body mass index (BMI) categorization in patients who received rivaroxaban therapy.

METHODS

This was a retrospective cohort study involving all patients who received rivaroxaban therapy across all Hamad Medical Corporation (HMC) hospitals from 2015 to 2020.

RESULTS

The number of patients initiated on rivaroxaban therapy significantly increased from 152 (3.3%) in 2015 to 1342 (28.9%) in 2020 (p <0.001). Within BMI categories, a similar increasing trend was observed in underweight, normal, and overweight patients, while from 2018 to 2020, there was a decreasing trend in rivaroxaban prescribing in all obese classes. The prevalence rate of all-cause mortality differed significantly between the BMI groups, with the highest mortality being among morbidly obese patients (BMI ≥ 40 kg/m2) (p< 0.001). On the other hand, no significant differences were found between the BMI groups in terms of bleeding, pulmonary embolism, deep vein thrombosis and stroke incidences. Multivariate logistic regression analyses showed that the likelihood of all-cause mortality was significantly higher in overweight and all categories of obese patients compared to underweight patients: overweight (OR: 5.3, 95% CI: 2.3-11.9, p< 0.001); obese class 1 (OR: 5.4, 95% CI: 2.3 - 12.2, p< 0.001); obese class 2 (OR: 6.5, 95% CI: 2.7 - 15.6, p< 0.001); and obese class 3 (OR: 3.7, 95% CI: 1.6 - 8.7, p = 0.003).

CONCLUSIONS

Rivaroxaban prescribing has significantly increased over the years across general population, with a noticeable decline in obese population during the last few years (from 2018 onwards). Furthermore, an appreciable association was evident between all-cause mortality and BMI of these patients.

A Real-World Comparison of Apixaban and Rivaroxaban in Obese and Morbidly Obese Patients With Nonvalvular Atrial Fibrillation

Background: Contemporary guidelines for managing nonvalvular atrial fibrillation (NVAF) include apixaban and rivaroxaban as first-line anticoagulation treatment options. Minimal guidance is available regarding selecting anticoagulants for patients with class I-III obesity. Objective: This study aims to evaluate the comparative effectiveness and safety of apixaban and rivaroxaban in both obese and morbidly obese patients with NVAF. Methods: A retrospective cohort study was conducted at an outpatient cardiovascular clinic after Institutional Review Board approval. Patients were eligible if they were ≥18 years of age, had a BMI ≥30 kg/m2, and took apixaban or rivaroxaban for NVAF for ≥3 months. The primary endpoint was the composite rate of stroke, transient ischemic attack (TIA), myocardial infarction (MI), or presence of atrial thrombosis. Bleeding events were evaluated as the primary safety endpoint. Results: Combined, the cohorts consisted of 303 obese or morbidly obese patients. The primary composite endpoint occurred in 3.8% of patients taking apixaban and 1.7% of patients taking rivaroxaban (P = .28). Both clinically relevant, non-major and major bleeding occurred more often in the apixaban arm, but this difference was not statistically significant; however, bleeding risk may have been skewed due to differences in baseline characteristics. Conclusion and Relevance: For obese and morbidly obese patients prescribed either apixaban or rivaroxaban for NVAF, rates of stroke, TIA, MI, and atrial thrombosis did not differ. The preferred DOAC for patients with class I-III obesity remains elusive, but current data points to a patient-centered approach for anticoagulant selection.

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

PURPOSE

We conducted a multicenter real-world study in China to assess the association between body mass index (BMI) and clinical outcomes in patients with atrial fibrillation (AF) taking direct oral anticoagulants (DOACs).

METHOD

This is a retrospective multicenter cohort study conducted in 15 centers in China. We collected demographic information through the hospital information system and obtained clinical events through follow-up visits to patients or relatives. Clinical outcomes include major, minor, total bleeding, thromboembolism, and all-cause death.

RESULT

A total of 6164 patients with non-valvular AF (NVAF) were included in this study. The incidence of major bleeding in patients with NVAF differed significantly by BMI category (P < 0.001), with 5.2% in the underweight group, 2.6% in the normal group, 1.4% in the overweight group, 1.1% in the obese I group, and 1.3% in the obese II group. There was no significant difference in minor, total bleeding, and thrombosis in the five groups (P = 0.493; P = 0.172; P = 0.663). All-cause death was significantly different among the five groups (P < 0.001), with 8.9% in the underweight group, 6.3% in the normal group, 4.8% in the overweight group, 2.2% in the obese I group, and 0.4% in the obese II group. High BMI was negatively associated with major bleeding (OR = 0.353, 95% CI 0.205-0.608), total bleeding (OR = 0.664, 95% CI 0.445-0.991), and all-cause death (OR = 0.370, 95% CI 0.260-0.527).

CONCLUSION

In patients with NVAF treated with DOACs, higher BMI was associated with lower major bleeding and better survival. BMI was a negative correlate of total bleeding, but not minor bleeding and thrombosis.

The Effectiveness and Safety of Direct Oral Anticoagulants in Obese Patients With Atrial Fibrillation: A Network Meta-Analysis

Atrial fibrillation (AF) is a cardiac condition characterized by an irregular heart rhythm, which is increasingly prevalent in the modern era. All international guidelines strongly advise the administration of anticoagulants to individuals with AF who are at high risk of stroke. These guidelines recommend the use of direct oral anticoagulants (DOACs) over warfarin because warfarin is significantly associated with increased rates of major bleeding, numerous interactions with food and drugs, and the necessity for frequent monitoring. The aim of this study is to compare the effectiveness and safety of direct oral anticoagulants (DOACs) in obese patients with atrial fibrillation. Two authors independently conducted a comprehensive literature search using electronic databases including PubMed, CINAHL, and EMBASE from inception to June 1, 2023. The efficacy outcome assessed in this meta-analysis included the composite of stroke and systemic embolism. For safety analysis, major bleeding events were compared among the study groups. Eleven studies fulfilled all the inclusion criteria and were included in the present meta-analysis enrolling 144,502 patients. In this study, DOACs demonstrate superior efficacy in preventing stroke/systemic embolism compared to warfarin. Among the DOACs, apixaban emerged as the most effective, followed by rivaroxaban, warfarin, and dabigatran. In terms of safety, apixaban was also found to be the most favorable treatment option, followed by rivaroxaban, dabigatran, and warfarin. In summary, our study concludes that apixaban exhibited greater effectiveness and safety when compared to other DOACs and warfarin in obese patients with AF.

Practices, beliefs, and attitudes of clinicians in prescribing direct oral anticoagulants for obese adults with atrial fibrillation: a qualitative study

BACKGROUND

Atrial fibrillation (AF) and obesity affect over 60 and 650 million people, respectively.

AIM

This study aimed to explore clinician practices, beliefs, and attitudes towards the use of direct oral anticoagulants (DOACs) in obese adults (BMI ≥ 30 kg/m²) with AF.

METHOD

Semi-structured interviews via video conference were conducted with multidisciplinary clinicians from across Australia, with expertise in DOAC use in adults with AF. Clinicians were invited to participate using purposive and snowball sampling techniques. Data were analysed in NVIVO using thematic analysis.

RESULTS

Fifteen clinicians including cardiologists (n = 5), hospital and academic pharmacists (n = 5), general practitioners (n = 2), a haematologist, a neurologist and a clinical pharmacologist participated. Interviews were on average 31 ± 9 min. Key themes identified were: Health system factors in decision-making Disparities between rural and metropolitan geographic areas, availability of health services, and time limitations for in-patient decision-making, were described; Condition-related factors in decision-making Clinicians questioned the significance of obesity as part of decision-making due to the practical limitations of dose modification, and the rarity of the extremely obese cohort; Decision-making in the context of uncertainty Clinicians reported limited availability, reliability and awareness of primary evidence including limited guidance from clinical guidelines for DOAC use in obesity.

CONCLUSION

This study highlights the complexity of decision-making for clinicians, due to the limited availability, reliability and awareness of evidence, the intrinsic complexity of the obese cohort and limited guidance from clinical guidelines. This highlights the urgent need for contemporary research to improve the quality of evidence to guide informed shared decision-making.

Warfarin Time in Therapeutic INR Range and Direct Oral Anticoagulant Adherence for Venous Thromboembolism Across the Spectrum of Weight and Body Mass Index: Findings from Veterans Health Administration

The evidence of direct oral anticoagulants (DOACs) usage for venous thromboembolism (VTE) in patients at extremes of body weight or mass index is limited. In such situations, warfarin may be more frequently used. We investigated warfarin time in the therapeutic international normalized ratio range (TTR) and DOAC adherence based on the calculated proportion of days covered (PDC) by pill coverage from a DOAC prescription in patients with VTE across all body sizes. Using data from the Veterans Health Administration (VA), we identified first-time patients with VTE between 2013 and 2018 treated with warfarin or DOACs. We analyzed 28,245 patients with warfarin TTR (N  =  10,167) or DOAC PDC(N  =  18,078). For warfarin-treated patients after index VTE, mean TTR was lower over shorter treatment durations (TTR 30 vs TTR 180 [mean  ±  SD]: 43.8% ± 33.5% vs 58.8% ± 23.5%). Mean TTR over 180 days after VTE was lowest for patients <60 kg (TTR 180 [mean  ±  SD]: <60kg: 49.3% ± 24.2% vs ≥60 to <100 kg: 57.8% ± 23.4%; P < .0001). For DOAC-treated patients over 180 days after index VTE, mean PDC was lowest for patients <60 kg (PDC 180 [mean  ±  SD]: < 60kg: 76.9% ± 33.2% vs ≥ 60 to <100 kg: 83.6% ± 27.7%; P < .0001).Most DOAC-treated patients attained sufficient adherence across the body size spectrum while warfarin-treated patients <60kg were at risk for low TTR.

Safety and efficacy of apixaban, dabigatran and rivaroxaban in obese and morbidly obese patients with heart failure and atrial fibrillation: A real-world analysis

BACKGROUND

Atrial fibrillation and heart failure are combined risk factors for thromboembolic events. Obese and morbidly obese individuals have been underrepresented in clinical trials studying safety and efficacy of direct oral anticoagulants (DOACs).

OBJECTIVES

Study the comparative safety and efficacy of DOACs in obese and morbidly obese patients with atrial fibrillation or flutter, and concomitant congestive heart failure.

METHODS

In the present single-center retrospective observational study, patients with an ICD-9 code of atrial fibrillation or atrial flutter, and congestive heart failure on a DOAC (apixaban[n = 155], rivaroxaban[n = 335], dabigatran[n = 393]) were followed for a median 12.5 months (IQR: 22.1 months). Obesity was defined as a body mass index, BMI ≥ 30 and < 40 kg/m² [n = 614], and morbid obesity as BMI ≥ 40 kg/m² [n = 269]. Clinical endpoints were grouped into safety (composite of intracranial-hemorrhage, gastrointestinal-bleeds, hemorrhagic-stroke, and other bleeds), and efficacy (composite of ischemic-stroke and systemic-embolism) endpoints. Cox proportional hazard models were used to compare safety, efficacy, and all-cause mortality outcomes.

RESULTS

In obese patients, no statistical difference was observed in efficacy of DOACs. A statistical difference was observed in the safety of DOACs in obese patients. Apixaban was found to be safer than dabigatran [hazard ratio [HR] 0.37 (0.16-0.87), p = .02] and rivaroxaban [HR 0.29 (0.12-0.67), p = .004]. In morbidly obese patients, there was no overall statistical difference in the efficacy or safety of DOACs.

CONCLUSION

In obese patients with congestive heart failure and atrial fibrillation or atrial flutter on DOACs, apixaban has the most favorable safety profile compared to rivaroxaban and dabigatran.

Comparing the Efficacy and Safety of Apixaban Versus Warfarin in Morbidly Obese Patients

This study was conducted to evaluate the efficacy and safety of apixaban versus warfarin in morbidly obese patients. A total of 250 morbidly obese patients with a body mass index (BMI) higher than 40 kg/m² or a body weight higher than 120 kg who were on anticoagulation therapy with either apixaban or warfarin for over one month were included in the study. This retrospective cohort, multicenter study was executed using the medical records of 125 morbidly obese patients treated with apixaban, while patients on warfarin were selected using a systemic random sampling to match the sample size of the apixaban group. There was no significant difference between apixaban and warfarin in the development of thromboembolic events and major bleeding. However, incidences of minor bleeding significantly decreased in the apixaban group compared to patients treated with warfarin. This difference was overcome by controlling serum creatinine and nonsteroidal anti-inflammatory drugs (NSAIDs). In conclusion, apixaban efficacy and safety are nearly the same as that of warfarin in morbidly obese patients with a lower incidence of minor bleeding with apixaban. Controlling serum creatinine and NSAIDs use may improve warfarin safety and decrease its complications.

Effectiveness and Safety of Dabigatran in Atrial Fibrillation Patients with Severe Obesity: a Real-World Retrospective Cohort Study

BACKGROUND

Direct oral anticoagulants such as dabigatran are the preferred anticoagulant in treating atrial fibrillation (AF) patients due to their effectiveness and safety. Whether this applies to severely obese patients needs to be determined.

OBJECTIVE

To compare the effectiveness and safety of dabigatran with warfarin among AF patients with severe obesity.

DESIGN

Retrospective cohort study.

PARTICIPANTS

AF patients with a BMI >40kg/m2 or a weight >120kg receiving dabigatran or warfarin between 10/01/2010 and 12/31/2019 in a large integrated health system and followed through 08/01/2020.

INTERVENTIONS

Not applicable.

MAIN MEASURES

Primary effectiveness outcome was composite thromboembolism including transient ischemic attack, ischemic stroke, or systemic embolism. Primary safety outcome was composite bleeding including gastrointestinal bleeding, intracranial bleeding, or other bleeding. Secondary outcomes included the individual outcomes and all-cause mortality. Propensity score matching (PSM) was performed to create a 1:1 matched cohort and Cox proportional hazards model was used to estimate the hazard ratio (HR) of each outcome for dabigatran users compared to warfarin users.

KEY RESULTS

A total of 6848 patients receiving either dabigatran or warfarin were identified. In a 1:1 matched cohort, dabigatran users had a HR of 0.71 (95% confidence interval (CI): 0.56-0.91) for composite thromboembolism, a HR of 1.24 (95%CI: 1.07-1.42) for composite bleeding, and a HR of 0.57 (95% CI: 0.45-0.71) for all-cause mortality when compared to warfarin users.

CONCLUSIONS

Among AF patients with a BMI >40kg/m2 or a weight >120kg in a real-world clinical setting, dabigatran was effective in reducing the risk of thromboembolism and mortality but was associated with an increased risk of bleeding when compared to warfarin. Dabigatran may be a reasonable option for AF patients with severe obesity.

Randomized evaluation of decision support interventions for atrial fibrillation: Rationale and design of the RED-AF study

BACKGROUND

Shared decision making (SDM) improves the likelihood that patients will receive care in a manner consistent with their priorities. To facilitate SDM, decision aids (DA) are commonly used, both to prepare a patient before their clinician visit, as well as to facilitate discussion during the visit. However, the relative efficacy of patient-focused or encounter-based DAs on SDM and patient outcomes remains largely unknown. We aim to directly estimate the comparative effectiveness of two DA's on SDM observed in encounters to discuss stroke prevention strategies in patients with atrial fibrillation (AF).

METHODS

The study aims to recruit 1200 adult patients with non-valvular AF who qualify for anticoagulation therapy, and their clinicians who manage stroke prevention strategies, in a 2x2 cluster randomized multi-center trial at six sites. Two DA's were developed as interactive, online, non-linear tools: a patient decision aid (PDA) to be used by patients before the encounter, and an encounter decision aid (EDA) to be used by clinicians with their patients during the encounter. Patients will be randomized to PDA or usual care; clinicians will be randomized to EDA or usual care.

RESULTS

Primary outcomes are quality of SDM, patient decision making, and patient knowledge. Secondary outcomes include anticoagulation choice, adherence, and clinical events.

CONCLUSION

This trial is the first randomized, head-to-head comparison of the effects of an EDA versus a PDA on SDM. Our results will help to inform future SDM interventions to improve patients' AF outcomes and experiences with stroke prevention strategies.

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

Evaluation of Apixaban safety and effectiveness in morbidly obese patients with atrial fibrillation: a retrospective cohort study

Background

The benefit of apixaban to reduce stroke risk in morbidly obese patients with nonvalvular atrial fibrillation (AF) is still undetermined. The International Society of Thrombosis and Hemostasis recommends avoiding the use of direct oral anticoagulants (DOAC)s in morbidly obese patients (body mass index > 40 or weight > 120 kg) because of limited clinical data. This exploratory study aims to evaluate the effectiveness and safety of using apixaban in morbidly obese (body mass index (BMI) ≥ 40) patients with AF.

Methods

An exploratory retrospective cohort study was conducted at a single-center, including adult patients with non-valvular AF using apixaban between 01/01/2016 and 31/12/2019. Patients were excluded if they were known to have liver cirrhosis Child-Pugh C, mechanical valve, serum creatinine > 1.5 mg/dL, follow up < 3 months, or using apixaban with a dose of ≤5 or > 10 mg/day. Included patients were categorized into two groups based on their BMI (BMI<40 Vs. BMI ≥ 40). The primary outcome was all thrombotic events, while the secondary outcomes were major and minor bleeding after apixaban initiation. Propensity score (PS) matching was used (1:1 ratio) based on the patient’s age, gender, and HAS-BLED score.

Results

A total of 722 patients were eligible; 254 patients were included after propensity score matching based on the selected criteria. The prevalence of all thrombotic events was similar between the two groups in the first year of apixaban initiation (OR (95%CI): 0.58 (0.13, 2.5), p-value = 0.46). In addition, the odds of developing major and minor bleeding were not statistically significant between the two groups (OR (95%CI): 0.39 (0.07, 2.03), p-value = 0.26 and OR (95%CI): 1.27 (0.56, 2.84), p-value = 0.40), respectively).

Conclusion

This exploratory study showed similar effectiveness and safety of apixaban use in both morbid and non-morbid obese patients with non-valvular AF. However, a larger randomized controlled trial with a longer follow-up period needs to confirm our findings.

Examination of the Effectiveness of Direct Oral Anticoagulants in Comparison to Warfarin in an Obese Population

Background: While commonly prescribed today, direct oral anticoagulants (DOACs) have historically been avoided in patients with class III obesity or a weight >120 kg due to limited literature regarding the efficacy and safety in this population. Objective: The overall objective was to examine the effectiveness of DOACs compared to warfarin in a population with obesity. Methods: Patients with a diagnosis of venous thromboembolism (VTE) or atrial fibrillation and a body mass index (BMI) ≥35 kg/m² from August 1, 2015, to August 1, 2020, were included in this retrospective cohort study. Patients receiving a DOAC were matched in a 1:2 ratio to warfarin. The primary outcome was a composite of stroke or recurrent VTE. Secondary outcomes included the individual components of the primary outcome, hospitalization for bleed, and the primary outcome in patients with a BMI ≥40 kg/m². Results: A total of 162 patients were included, with 54 and 108 in the DOAC and warfarin groups, respectively. Baseline BMI was similar between groups (45.7 kg/m² for DOACs vs 43.8 kg/m² for warfarin), with approximately 70% of patients having a BMI ≥40 kg/m². The primary outcome occurred in 1 patient (1.9%) in the DOAC group and 2 patients (1.9%) in the warfarin group. The DOAC group had a higher, nonsignificant incidence of bleeding (5.6% vs 0.9%, P = 0.11). There was no difference between groups in incidence of deep vein thrombosis (DVT), pulmonary embolism (PE), or stroke in patients with a BMI ≥40 kg/m². Conclusion: DOACs may be as efficacious as warfarin in the prevention of stroke or recurrent VTE in patients with a BMI of ≥35 kg/m². Prospective, randomized trials are warranted to further assess the efficacy and safety of DOACs in this population.

Comparative Effectiveness and Safety of DOAC Versus Warfarin among Obese Patients with Atrial Fibrillation

Background

Obese patients are underrepresented in clinical trials assessing the comparative effectiveness and safety of use of direct oral anticoagulants vs use in atrial fibrillation (AF) patients.

Methods

Using data from Quebec provincial administrative databases, for the years2010-2017, we created a retrospective cohort of patients with inpatient or outpatient coding for AF and obesity who were newly prescribed an oral anticoagulant. The primary safety outcome was a composite of intracranial, gastrointestinal, and major bleeding from other sites, and the primary effectiveness outcome was a composite of ischemic stroke, systemic embolism, acute myocardial infarction, and death in the first year after oral anticoagulant initiation. Treatment groups were compared using inverse-probability-of-treatment-weighting Cox proportional-hazards models.

Results

A total of 2263 patients were included, of whom 1253, 403, and 539 filled a warfarin, standard-dose rivaroxaban, and standard-dose apixaban prescription, respectively. Standard-dose rivaroxaban was associated with a similar composite safety (hazard ratio [HR] 0.91; 95% confidence interval [CI] 0.44-1.91) and composite effectiveness risk (HR 1.42; 95% CI 0.99-2.04) compared to warfarin, whereas standard-dose apixaban was associated with a lower composite safety (HR 0.40; 95% CI 0.16-0.98) and similar composite effectiveness risk (HR 0.96; 95% CI 0.67-1.39).

Conclusion

Use of direct oral anticoagulants in obese AF patients was associated with a similar effectiveness and safety profile to that of warfarin use.

Direct oral anticoagulants in patients with nonvalvular atrial fibrillation and extreme body weight

BACKGROUND

Limited clinical data exist describing the use of direct oral anticoagulants (DOACs) in patient with extreme body weight. Thus, the International Society of Thrombosis and Haemostasis (ISTH) recommends avoiding DOACs in patients with weight >120 Kg, and on the contrary, no restrictions exist for underweight patients.

OBJECTIVE

To evaluate the effects of extreme body weight on DOAC activity and to compare the clinical outcomes of patients with an extreme body weight versus patients with a normal weight (61-119 Kg) treated with DOACs.

METHODS

Single tertiary care Italian centre multidisciplinary registry including nonvalvular atrial fibrillation (NVAF) patients treated with DOACs. Based on weight, three subcohorts were defined: (i) underweight patients (≤60 Kg); (ii) patients with a normal weight (61-119 Kg, as control group); and (iii) overweight patients (≥120 Kg). Primary efficacy endpoint was 2-year rate of thromboembolic events. Primary safety endpoint was 2-year rate of major bleeding. Event-free survival curves among groups were compared using Cox-Mantel test.

RESULTS

812 NVAF patients were included, 108 patients weighed ≤60 Kg (13%, underweight), 688 weighed between 61 and 119 Kg (85%, normal weight), and 16 weighed ≥120 Kg (2%, overweight). In particular, among underweight patients, dabigatran was prescribed in 26% patients, apixaban in 27%, rivaroxaban in 28% and edoxaban in 22% ones. Instead, among overweight patients, 44% were treated with dabigatran, 25% with apixaban, 25% with rivaroxaban and 4% with edoxaban. Underweight patients were older, more frequently women, with lower creatinine clearance and a history of previous strokes, resulting in higher CHA2DS2-VASc score than in both remaining groups. Up to 2 years, no statistically significant difference was observed between the three groups of weight for thromboembolic events (P = .765) and for overall bleeding (P = .125), but a trend towards decreased overall bleeding rates was noticed as weight increased (24.1% vs 16.7% vs 12.5%, respectively).

CONCLUSION

In this tertiary care centre registry, 15% of patients treated with DOACs presented an extreme weight. Compared to patients with a normal weight, no significant rates of thromboembolic events were observed for underweight or overweight patients. A trend towards decreased overall bleeding frequency as weight increased was highlighted up to 2 years. The present results should be considered as preliminary and hypothesis generating.

Real life behaviour of direct oral anticoagulants in patients with nonvalvular atrial fibrillation and morbid obesity

Atrial fibrillation (AF) is the most prevalent arrhythmia worldwide and the main cause of anticoagulation, being direct oral anticoagulants (DOAC) increasingly used in this context. On the other hand, obesity is a known risk thromboembolic factor. In the clinical trials that led to the approval of DOAC for ischemic stroke prevention, patients with morbid obesity were underrepresented. The International Society of Thrombosis and Haemostasis suggests not using these drugs in morbid obese patients. Thus, the primary objectives of this study were to analyse the rates of mortality, thrombotic and haemorrhagic events in patients with morbid obesity. As secondary objectives, factors statistically associated with these events were analysed. Methods: multicentre retrospective study that included patients diagnosed with AF on treatment with DOAC from January 2013 to December 2016. The subgroup of patients with morbid obesity (BMI > 40 and / or weight > 120 kg) was analysed. Mean follow-up was 1.7 years. Results: Amongst 2,492 patients included in the study, 135 patients had morbid obesity (mean age was 71 ± 11 years). The mean scores of the CHA2DS2-VASc and HAS-BLED risk scales were 3.7 ± 1.6 and 2.2 ± 0.9, respectively. Neither differences were found regarding mortality (5.2 vs 6/100 patient-years, p = 0.662), ischemic stroke (0.8 vs 1.9/100 patient-years, p = 0.261) and major bleeding rates (3 vs 3.1/100 patient-years, p = 0.983) between morbidly obese population and general population. Nor was there an association found between the degree of obesity and any of the events studied. Conclusion: DOAC are safe and effective in morbidly obese patients.

Oral Anticoagulant Use in Morbid Obesity and Post Bariatric Surgery: A Review

Bariatric surgery has emerged as a therapy for obesity and the associated comorbidities. Obesity has been shown to be a risk factor for atrial fibrillation as well as venous thromboembolism, both of which are conditions that warrant anticoagulation. There is significant underrepresentation of the morbidly obese population in prospective trials that evaluated direct oral anticoagulants and vitamin K antagonists in atrial fibrillation and venous thromboembolism. We aim to review all the available data that assessed these oral anticoagulants in the morbidly obese population (body mass index >40 kg/m² and weight >120 kg) and in the post-bariatric surgery population. Our findings suggest that direct oral anticoagulants may be safe and effective for anticoagulation in morbidly obese patients for both atrial fibrillation and venous thromboembolism. However, warfarin is the preferred agent in the post-bariatric surgery population, given the limited number of studies on direct oral anticoagulants in this population. Further adequately powered randomized control trials are needed to confirm the safety and efficacy of these oral anticoagulants in the morbidly obese and post-bariatric surgery population.

Apixaban and rivaroxaban use for atrial fibrillation in patients with obesity and BMI ≥50 kg/m2

BACKGROUND

Apixaban and rivaroxaban are increasingly used for thromboembolism prophylaxis in patients with non-valvular atrial fibrillation (NVAF) and commonly in patients with obesity and body mass index (BMI) ≥50 kg/m² despite the limited data.

OBJECTIVES

This study aimed to establish the effectiveness and safety of apixaban and rivaroxaban in patients with NVAF and BMI ≥50 kg/m² .

METHODS

A single health-system, retrospective cohort study evaluated the effectiveness and safety of apixaban and rivaroxaban initiated in adult patients (≥18 years of age) with BMI ≥50 kg/m² and NVAF. Outcomes of ischemic stroke, systemic embolic events, and bleeding were compared to a cohort of patients with BMI 18 to 30 kg/m² .

RESULTS

After 1619 patient-years worth of follow-up in 595 patients, the primary endpoint of incidence of ischemic stroke was numerically similar in both groups, 1.3 per 100 patient-years in the BMI ≥50 kg/m²  group, compared to 2.0 per 100 patient-years in the BMI <30 kg/m²  group (RR 0.65, 95% CI 0.38-1.82, p = 0.544). Incidence of major bleeding and clinically relevant non-major bleeding was also numerically similar between the two groups.

CONCLUSIONS

This study demonstrated that apixaban and rivaroxaban in patients with a BMI ≥50 kg/m² for treatment of NVAF may be safe and effective at preventing thromboembolic events and had no increased risk of bleeding. Although, findings should be interpreted with caution and confirmed with additional studies. This study contributes to the growing body of evidence that direct oral anticoagulants (DOACs) may be effective and safe to use for the treatment of NVAF in patients with BMI ≥50 kg/m² .

Clinical outcomes of dabigatran use in patients with non-valvular atrial fibrillation and weight >120 kg

BACKGROUND

Patients with obesity were underrepresented in studies evaluating the safety and effectiveness of direct oral anticoagulants (DOAC) in patients with non-valvular atrial fibrillation (NVAF). This study compared clinical outcomes in patients with NVAF and weighing >120 kg and ≤120 kg who were receiving dabigatran.

MATERIALS AND METHODS

This retrospective, matched, longitudinal cohort study included patients from three integrated healthcare delivery systems. Patients ≥18 years of age with NVAF were included if between September 1, 2016 and June 30, 2019 they received dabigatran. Patients >120 kg and ≤120 kg were matched up to 1:6 on age, sex, and CHA₂DS₂-VASc score. Data were extracted from administrative databases. The primary outcome was a composite of ischemic stroke, clinically-relevant bleeding, systemic embolism, and all-cause mortality. Multivariable regression analyses were performed.

RESULTS

777 and 3522 patients >120 kg and ≤120 kg, respectively, were matched. The >120 kg group tended to be younger with a higher burden of chronic disease. There was no difference between groups in the composite outcome (adjusted hazard ratio [AHR] 1.10, 95% confidence interval 0.89-1.37) or individual components of the composite. A subanalysis of clinically-relevant bleeding identified that patients >120 kg were at a greater risk of gastrointestinal bleeding (AHR 1.44, 95% CI 1.01-2.05).

CONCLUSIONS

In patients with NVAF and >120 kg, dabigatran use was associated with a small increased risk of gastrointestinal bleeding but no differences in stroke, mortality or clinically-relevant bleeding. These findings suggest that dabigatran use is reasonable in patients with NVAF and weight >120 kg.

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

BACKGROUND

Consensus statements have recommended against the use of direct oral anticoagulants (DOACs) in venous thromboembolism (VTE) for patients ≥120 kg and ≥40 kg/m². We sought to determine use and outcomes of DOACs for VTE across weight and body mass index (BMI).

METHODS

We performed a retrospective cohort study of patients with first-time VTE 2013 to 2018 that were treated with DOAC or warfarin in the Veterans Health Administration. The Veterans Health Administration has implemented system-wide guidance for patient selection and shared decision-making for use of DOACs in VTE at extremes of weight. We stratified patients by weight and BMI and assessed (1) association of weight and BMI category to outcomes in those prescribed DOAC; and (2) association of DOAC, as compared to warfarin, to outcomes by weight and BMI categories. Outcomes of interest included major bleeding, clinically relevant nonmajor bleeding, and recurrent VTE.

RESULTS

The analysis cohort included 51 871 patients prescribed DOAC or warfarin within 30 days of index VTE diagnosis (age 64.5±13.1 years; 6.0% female; median weight 93.4 kg [25th-75th: 80.5-108.6 kg]). For patients ≥120 kg (N=6934 patients), 38.4% were treated with DOAC, as compared to 45.4% of those ≥60 to <100 kg (N=30 645; P<0.0001). DOAC prescription was not associated with major bleeds, clinically relevant nonmajor bleeds, or recurrent VTE for those in higher weight and BMI categories as compared to those in average weight and BMI categories. DOAC prescription, as compared to warfarin, was not associated with increased recurrent VTE in any weight or BMI category.

CONCLUSIONS

Patients ≥120 kg and ≥40 kg/m² with VTE are frequently prescribed DOAC by the Veterans Health Administration, without an increase in bleeding or recurrent VTE. These findings suggest DOACs can be safe and effective in this population and may argue for broader adoption of pharmacy policies that promote careful patient selection and shared decision making.

Effectiveness of Direct Oral Anticoagulants in Obese Adults With Atrial Fibrillation: A Systematic Review of Systematic Reviews and Meta-Analysis

Background: Atrial Fibrillation (AF) is the most common sustained cardiac arrhythmia. Obesity is an independent risk factor for AF. Anticoagulants have been strongly recommended by all international guidelines to prevent stroke. However, altered pathophysiology in obese adults may influence anticoagulant pharmacology. Direct oral anticoagulants (DOACs) in the context of obesity and AF have been examined in recent systematic reviews. Despite the similarities in included studies, their results and conclusions do not agree.

Methods and Results: The protocol for this review was registered with PROSPERO (CRD42020181510). Seven key electronic databases were searched using search terms such as “atrial fibrillation,” “obese,^*” “overweight,” “novel oral anticoagulant,” “direct oral anticoagulant,” “DOAC,” “NOAC,” “apixaban,” dabigatran,” “rivaroxaban,” and “edoxaban” to locate published and unpublished studies. Only systematic reviews with meta-analyses that examined the effect of DOACs in overweight or obese adults with AF, published in the English language, were included. A total of 9,547 articles were initially retrieved. After removing the duplicates, title and abstract review and full-text review, five articles were included in the systematic review. From these only RCTs were included in the meta-analyses. There was disagreement within the published systematic reviews on DOACs in obesity. The results from our meta-analysis did not show any significant difference between all body mass index (BMI) groups for all outcomes at both 12 months and for the entire trial duration. Non-significant differences were seen among the different types of DOACs.

Conclusion: There was no difference between the BMI classes in any of the outcomes assessed. This may be due to the limited number of people in the trial that were in the obese class, especially obese class III. There is a need for large prospective trials to confirm which DOACs are safe and efficacious in the obese class III adults and at which dose.

Effectiveness and Safety of Direct Oral Anticoagulants in Patients with Nonvalvular Atrial Fibrillation and Weighing ≥ 120 Kilograms versus 60-120 Kilograms

BACKGROUND

Direct oral anticoagulants (DOACs) have become favorable choices for anticoagulation due to their fixed-dose schedule, limited need for monitoring, and non-inferiority or superiority to warfarin. DOACs are currently not recommended in patients with a body weight ≥ 120 kg or body mass index ≥ 40 kg/m² due to limited data regarding safety and efficacy.

OBJECTIVE

The aim of this study was to compare the safety and efficacy of DOACs in patients with nonvalvular atrial fibrillation (NVAF) and weighing ≥ 120 kg with those weighing < 120 kg.

METHODS

A single-center, retrospective study was conducted in patients weighing ≥ 120 kg who received either apixaban, dabigatran, or rivaroxaban for stroke risk reduction in NVAF, and matched to patients who weighed < 120 kg. The primary outcome was the incidence of stroke, deep vein thrombosis, pulmonary embolism, or myocardial infarction, while the safety outcome was the incidence of major or clinically relevant non-major bleeding based on the International Society on Thrombosis and Haemostasis (ISTH) definitions.

RESULTS

A total of 318 patients weighing ≥ 120 kg with NVAF and meeting the inclusion criteria were evaluated and matched with 318 patients weighing < 120 kg. The primary outcome occurred in 2.5% of patients in the ≥ 120 kg group and in 3.1% of patients in the < 120 kg group (p = 0.632). The safety outcome occurred in 5.3% and 6.6% of patients in these respective groups (p = 0.503).

CONCLUSION

Apixaban, dabigatran, or rivaroxaban may be well-tolerated and effective anticoagulant options in patients with NVAF weighing ≥ 120 kg.

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.

Pharmacokinetics of Direct Oral Anticoagulants in Patients With Atrial Fibrillation and Extreme Obesity

PURPOSE

Direct oral anticoagulants (DOACs) are recommended in preference to vitamin K antagonists (VKAs) for stroke prevention in patients with atrial fibrillation (AF) eligible for oral anticoagulation therapy; however, data and clinical experiences supporting the use of DOACs in patients with a body mass index ≥40 kg/m² or weight >120 kg remain limited. The aim of this study was to evaluate the pharmacokinetic properties of DOACs in patients with AF and extreme obesity.

METHODS

We enrolled all consecutive patients with AF and extreme obesity undergoing treatment with DOACs followed up at Monaldi Hospital, Naples, Italy. To determine peak plasma and trough levels of DOACs, plasma samples were collected at 2nd, 4th, 6th, and 12th hours from the last dose intake in patients receiving apixaban and dabigatran and at the 2nd, 4th, 6th, and 24th hours in those receiving edoxaban and rivaroxaban. The DOACs' peak and trough plasma levels obtained from our study population were compared with those sourced from pharmacokinetic studies among patients without obesity, defined as a normal reference range in the literature. If at least 1 peak or trough plasma level was found ​​below or above the normal reference ranges, the patients were classified as having out-of-range DOAC plasma levels. Study population was then divided into in-range and out-of-range groups. Baseline characteristics, including DOAC treatment, were compared between the 2 groups. Univariate and multivariate logistic regression analysis were performed to identify baseline variables associated with DOACs' plasma concentration out of the expected range.

FINDINGS

A total of 58 patients (mean [SD] age, 70.93 [8.73] years; 40% female) with extreme obesity (mean [SD] body mass index. 44.43 [3.54] kg/m²) and AF while undergoing DOAC treatment were included in the present study. In 9 patients (15.5 %), the DOAC plasma concentrations were out of the expected ranges (out-of-range group);, indicating a greater likelihood of edoxaban 30 mg treatment (33% vs 2%; P < 0.01) and inappropriate DOAC underdosing (56% vs 4%; P < 0.005) compared with the in-range group. According to the multivariate logistic analysis (P = 0.0011), the inappropriate DOAC underdosing (hazard ratio = 29.37; P = 0.0002) was an independent predictor of DOAC plasma levels out of the expected ranges.

IMPLICATIONS

Patients with extreme obesity and AF who were receiving DOAC therapy had DOAC plasma concentrations in the expected range. The inappropriate DOAC underdosing seems to be the only independent clinical factor associated with a plasma concentration of the drug out of the expected range.

Comparative Effectiveness and Safety of Rivaroxaban and Warfarin Among Nonvalvular Atrial Fibrillation (NVAF) Patients with Obesity and Polypharmacy in the United States (US)

Introduction

Current evidence indicates that rivaroxaban may be a safe and effective alternative to warfarin among patients with nonvalvular atrial fibrillation (NVAF) and obesity. However, evidence regarding the impact of polypharmacy is limited in this population. The present study evaluated the effectiveness and safety of rivaroxaban versus warfarin among NVAF patients with obesity and polypharmacy in the US.

Methods

De-identified health insurance claims data from the IQVIA PharMetrics^® Plus data (01/2010–09/2019) were used to identify NVAF patients with obesity (BMI ≥ 30 kg/m²) and polypharmacy (≥ 5 medications) initiated on rivaroxaban or warfarin. Inverse probability of treatment weighting (IPTW) was used to adjust for imbalances between groups. Study outcomes were evaluated up to 36 months post-treatment initiation and included the composite of stroke or systemic embolism (stroke/SE) and major bleeding. Subgroup analyses were conducted stratified by polypharmacy category (5–9 or ≥ 10 medications). Outcomes were assessed using Cox proportional hazards regression models with hazard ratios (HR) and 95% confidence intervals (CIs).

Results

A total of 7000 and 3920 NVAF patients with obesity and polypharmacy were initiated on rivaroxaban and warfarin, respectively. At 36 months of follow-up, rivaroxaban was associated with a 29% lower risk of stroke/SE relative to warfarin (HR 0.71, 95% CI 0.57, 0.90). Major bleeding risk was not significantly different among rivaroxaban- compared to warfarin-treated patients (HR 0.85, 95% CI 0.70, 1.03). Subgroup analyses yielded results that were largely consistent with the overall polypharmacy analysis.

Conclusions

These results suggest that rivaroxaban is an effective and safe treatment option among NVAF patients with obesity and polypharmacy in a commercially-insured US population.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01746-2.

Impact of Weight on Clinical Outcomes of Edoxaban Therapy in Atrial Fibrillation Patients Included in the ETNA-AF-Europe Registry

Background: Extremes of body weight may alter exposure to non-vitamin K antagonist oral anticoagulants and thereby impact clinical outcomes. This ETNA-AF-Europe sub-analysis assessed 1-year outcomes in routine care patients with atrial fibrillation across a range of body weight groups treated with edoxaban. Methods: ETNA-AF-Europe is a multinational, multicentre, observational study conducted in 825 sites in 10 European countries. Overall, 1310, 5565, 4346 and 1446 enrolled patients were categorised into ≤60 kg, >60–≤80 kg (reference weight group), >80–≤100 kg and >100 kg groups. Results: Patients weighing ≤60 kg were older, more frail and had a higher CHA₂DS₂-VASc score vs. the other weight groups. The rates of stroke/systemic embolism, major bleeding and ICH were low at 1 year (0.82, 1.05 and 0.24%/year), with no significant differences among weight groups. The annualised event rates of all-cause death were 3.50%/year in the overall population. After adjustment for eGFR and CHA₂DS₂-VASc score, the risk of all-cause death was significantly higher in extreme weight groups vs. the reference group. Conclusions: Low rates of stroke and bleeding were reported with edoxaban, independent of weight. The risk of all-cause death was higher in extremes of weight vs. the reference group after adjustment for important risk modifiers, thus no obesity paradox was observed.

Direct Oral Anticoagulants Versus Warfarin in Morbidly Obese Patients With Nonvalvular Atrial Fibrillation: A Systematic Review and Meta-analysis

BACKGROUND

Direct oral anticoagulants (DOACs) have been increasingly preferred over warfarin; however, The International Society of Thrombosis and Hemostasis recommended avoiding the use of DOACs in morbidly obese patients (body mass index >40 or weight >120 kg) because of limited clinical data.

STUDY QUESTION

Are DOACs effective and safe in morbidly obese patients with nonvalvular atrial fibrillation (NVAF).

DATA SOURCES

We performed a comprehensive search for published studies indexed in PubMed/MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials that evaluated the efficacy and safety of DOACs in morbidly obese patients with NVAF.

STUDY DESIGN

Information on patient characteristics, comorbidities, primary anticoagulation indications, pharmacologic treatment, and outcomes were collected. The primary outcome of interest was stroke or systemic embolism (SSE) rate. The secondary outcome was major bleeding (MB).

RESULTS

A total of 10 studies including, 89,494 morbidly obese patients with NVAF on oral anticoagulation therapy (45,427 on DOACs vs. 44,067 on warfarin) were included in the final analysis. The SSE rate was significantly lower in DOACs group compared with warfarin group [odds ratio: 0.71; 95% confidence interval (CI): 0.62-0.81; P < 0.0001; I2 = 0%]. MB rate was also significantly lower in DOACs group compared with the warfarin group (odds ratio: 0.60; 95% CI: 0.46-0.78; P < 0.0001; I2 = 86%). On subgroup analysis, SSE and MB event rates were significantly lower in rivaroxaban and apixaban than warfarin; however, dabigatran showed noninferiority to warfarin in SSE rate but superiority in the safety outcome.

CONCLUSIONS

Our meta-analysis demonstrated that DOACs are effective and safe with statistical superiority when compared with warfarin in morbidly obese patients. Large-scale randomized clinical trials are needed to further evaluate the efficacy and safety of DOACs in this cohort of patients.

Real-world effectiveness and safety of rivaroxaban versus warfarin among non-valvular atrial fibrillation patients with obesity in a US population

OBJECTIVES

Current evidence indicates that the pharmacokinetic profile of rivaroxaban is not significantly impacted by body weight. However, real-world data are needed to better assess the potential clinical benefits and risks associated with rivaroxaban in non-valvular atrial fibrillation (NVAF) patients with obesity. Thus, our objectives were to assess the real-world effectiveness and safety of rivaroxaban versus warfarin among NVAF patients with obesity in the US nationally representative commercially-insured population.

METHODS

Health insurance claims data from the IQVIA PharMetrics Plus database (January 2010-September 2019) were used to identify NVAF patients with obesity (based on diagnosis codes) initiated on rivaroxaban or warfarin. Inverse probability of treatment weighting (IPTW) was used to adjust for imbalances between groups. Study outcomes of interest were evaluated up to 36 months post-treatment initiation and included the composite of stroke or systemic embolism (stroke/SE) and major bleeding. Outcomes were compared using Cox proportional hazards regression models with hazard ratios (HR) and 95% confidence intervals (CIs).

RESULTS

A total of 10,555 patients were initiated on rivaroxaban and 5080 patients on warfarin. Following IPTW, the risk of stroke/SE was 26% lower among patients prescribed rivaroxaban relative to warfarin (HR: 0.74, 95% CI: 0.60, 0.91, p = .004) at 36 months. Rivaroxaban-initiated patients had a risk of major bleeding similar to that of warfarin-initiated patients (HR: 0.85, 95% CI: 0.71, 1.02, p = .085).

CONCLUSIONS

These results suggest that rivaroxaban is an effective and safe treatment option among NVAF patients with obesity in a commercially-insured US population.

Stroke due to Left Atrial Appendage Thrombus after Pulmonary Vein Isolation despite Novel Oral Anticoagulant: A Case Report

In patients with atrial fibrillation, catheter ablation is suggested to reduce the mortality rate and is thus frequently performed. However, peri- and postprocedural thromboembolic complications as well as high recurrence rates of atrial fibrillation limit its advantages and require concomitant anticoagulation. With the advent of novel oral anticoagulants (NOACs), fixed dosing without routine laboratory monitoring became feasible. Nevertheless, several factors are associated with either an overdose or an insufficient drug activity of NOACs. We report on a patient with atrial fibrillation undergoing catheter ablation and cardioversion suffering from ischemic stroke despite being under oral anticoagulation. It turned out that the drug activity of the NOACs used was repeatedly insufficient in spite of regular intake and adequate dosing. In sum, drug activity controls should be taken into consideration in patients with thrombotic events despite oral anticoagulation with NOACs.

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.

Outcomes of Direct Oral Anticoagulants in Atrial Fibrillation Patients Across Different Body Mass Index Categories

OBJECTIVES

This study sought to evaluate direct oral anticoagulant (DOAC) outcomes (vs. warfarin) in patients with atrial fibrillation (AF) across body mass index (BMI) categories, including ≥40 and <18.5 kg/m².

BACKGROUND

Clinical trials have not systematically tested the fixed DOAC dosing in underweight and morbidly obese patients.

METHODS

We retrospectively included consecutive patients with nonvalvular AF with CHA₂DS₂-VASc (Congestive heart failure, Hypertension, Age ≥75, Diabetes, Stroke/transient ischemic attack/systemic thromboembolism, Vascular disease, Age 65-74, Sex) of ≥1 receiving OACs at our hospital system (2010-2018). Patients were categorized into groups 1 (underweight: BMI of <18.5 kg/m²), 2 (normal/overweight: BMI of 18.5 to <30 kg/m²), 3 (grade 1/2 obesity: BMI of 30 to <40 kg/m²), and 4 (grade 3 obesity: BMI of ≥40 kg/m²). We further classified patients by DOAC versus warfarin use. Outcomes were ischemic stroke, significant bleeding events (i.e., resulting in hospitalization), and mortality.

RESULTS

We included 36,094 patients with a mean age of 74 ± 11 years and CHA₂DS₂-VASc of 3.4 ± 1.5. Groups 1 through 4 included 455 (1.3%), 18,339 (50.8%), 13,376 (37.1%), and 3,924 (10.9%) patients, respectively. DOAC use ranged from 49% to 56%. At 3.8 follow-up years, with multivariable Cox regression, DOACs (vs. warfarin) were associated with lower risk of ischemic stroke, bleeding, and mortality across all BMI groups, with hazard ratios (HRs) of 0.73 (95% confidence interval [CI]: 0.63 to 0.85), 0.75 (95% CI: 0.64 to 0.87), 0.75 (95% CI: 0.65 to 0.88), and 0.75 (95% CI: 0.64 to 0.87) (p < 0.001 for all) for ischemic stroke; 0.42 (95% CI: 0.19 to 0.92), 0.41 (95% CI: 0.19 to 0.89), 0.45 (95% CI: 0.20 to 1.00), and 0.43 (95% CI: 0.20 to 0.94) (p < 0.05 for all) for bleeding; and 0.90 (95% CI: 0.68 to 1.19; p = 0.5), 0.70 (95% CI: 0.66 to 0.75; p < 0.0001), 0.65 (95% CI: 0.60 to 0.71; p < 0.0001), and 0.66 (95% CI: 0.56 to 0.77; p < 0.0001) for mortality, in groups 1 to 4, respectively.

CONCLUSIONS

In patients with nonvalvular AF, DOACs compared to warfarin were associated with better safety and effectiveness across all BMI categories, including underweight and morbidly obese patients.

Efficacy and safety of direct oral anticoagulant in morbidly obese patients with atrial fibrillation: systematic review and meta-analysis

AIMS

We conducted a systematic review and meta-analysis on 3 outcomes. We assessed the efficacy and safety of direct oral anticoagulants (DOAC) compared to vitamin K antagonists (VKA) in morbidly obese patients with atrial fibrillation (AF). We compared the efficacy and safety of DOAC in obese patients and non-obese patients with AF. Finally, we updated the current knowledge of outcomes of AF patients with obesity compared to normal-weight patients regardless of anticoagulation type.

METHODS AND RESULTS

Using PubMed and Embase, we searched for literature published from inception to August 2020 for studies conducted in morbidly obese patients with AF who used DOACs and/or VKA for stroke or systemic embolism (stroke/SE) prevention that report efficacy and/or safety data. GRADE assessment was performed to determine the quality of the meta-analysis results. DOAC was not statistically different from VKA in reducing stroke/SE with RR of 0.85 (95%CI: 0.56 to 1.29; very low certainty evidence). Major bleeding risk was lower in the DOAC groups with RR of 0.62 (95%CI: 0.48 to 0.80; low certainty evidence). Obese patients with AF who used DOACs had lower risk of stroke/SE and similar major bleeding risk compared to nonobese patients with RR of 0.77 (95%CI: 0.70 to 0.84; low certainty evidence) and 1.02 (95%CI: 0.94 to 1.09; low certainty evidence), respectively. Obese patients with AF who used any type of anticoagulant had lower risk of stroke/SE compared to normal-weight patients with RR of 0.62 (95%CI: 0.57 to 0.69; low certainty evidence).

CONCLUSIONS

The use of DOACs in morbidly obese patients maybe reasonable if needed, but more dedicated studies are needed to make a more robust recommendation.

Safety and Efficacy of Rivaroxaban and Apixaban in Patients with Increased Body Mass: a Systematic Review

BACKGROUND AND OBJECTIVE

Rivaroxaban and apixaban are direct oral anticoagulants increasing in popularity as convenient alternatives to warfarin. However, current guidelines recommend against use in patients with a BMI > 40 kg/m² or bodyweight > 120 kg unless drug-specific levels are measured, which may not be feasible across all clinical practices. Accordingly, the objective of this study was to broadly examine literature evaluating the clinical outcomes of rivaroxaban and/or apixaban in patients with increased body mass.

METHODS

A systematic literature review (guided by PRISMA) was performed through January 27, 2021 using PubMed, Embase, and Scopus. Key search term clusters included drug and weight-related concepts (overweight/obese, body mass index [BMI], waist circumference). DistillerSR was utilized to review and process search results. Studies met inclusion if they analyzed the risk of bleeding and/or thrombosis in patients with increased body mass (i.e., via BMI or other criteria) receiving rivaroxaban or apixaban. Clinical guidelines, case reports/series, pharmacokinetic/dynamic analyses, and commentaries were excluded. Bias was examined qualitatively across studies.

RESULTS

After duplicates were removed, the original search rendered 1822 abstracts and 200 full-texts for screening, ultimately providing a final set of 24 studies for qualitative review. Of these studies, 13 (54.2%) enabled comparisons between patients of increased versus normal body mass, while 11 (45.8%) reported outcomes only for patients of increased body mass. The working definition of 'increased body mass' varied amongst the studies, including 11 (45.8%) studies that utilized BMI, seven (29.2%) with a combination of BMI and body measurement, two (8.3%) that relied on body weight alone, and four (16.7%) that identified obesity-related ICD codes. All 13 comparative studies found similar or reduced rates of safety and efficacy outcomes with rivaroxaban and apixaban.

CONCLUSION

The literature reports similar or lower bleeding and thrombotic risk for rivaroxaban and apixaban in patients of increased body mass compared to patients of normal body mass. Future prospective controlled studies are needed to further define guidelines for use in this population.

Direct Oral Anticoagulant Use in Special Populations: Elderly, Obesity, and Renal Failure

PURPOSE OF REVIEW

The purpose of this review is to examine the safety and effectiveness of direct oral anticoagulants and provide recommendations for the treatment of venous thromboembolism and atrial fibrillation in obese patients, elderly patients, and patients with chronic kidney disease.

RECENT FINDINGS

Multiple retrospective cohort studies have shown no difference in bleeding, stroke, or venous thromboembolism outcomes between DOACs and warfarin in patients who are obese, elderly, or those with chronic kidney disease or on dialysis. Some studies have shown that DOACs have a lower bleeding risk than warfarin in these populations. DOACs may be a safe and effective alternative to warfarin for the prevention of stroke in atrial fibrillation patients who are obese, elderly, or those with chronic kidney disease or on dialysis. Apixaban may improve clinical outcomes by lowering the risk of bleeding versus warfarin. DOACs may also be an effective and safe alternative to warfarin for the treatment of venous thromboembolism in obese patients; however, additional studies are needed to assess their use in elderly patients and those with CKD.

Comparative Effectiveness and Safety of Direct Oral Anticoagulants in Obese Patients with Atrial Fibrillation

BACKGROUND

Unlike warfarin direct oral anticoagulants (DOACs) are administered in fixed doses, which raises concerns of its effectiveness on larger patients. Data from randomized trials are limited on the safety and efficacy of DOACs in morbidly obese individuals with atrial fibrillation (AF).

METHODS

We analyzed a cohort of obese (≥ 120 kg) and morbidly obese (BMI > 40 kg/m²) patients from the Veterans Health Administration system with AF who initiated apixaban, rivaroxaban, dabigatran, or warfarin between years 2012 and 2018. We used inverse probability of treatment weighting (IPTW) and Cox proportional hazards regression models to evaluate the relative hazard of death, myocardial infarction (MI), ischemic stroke, heart failure (HF), and bleeding events between oral anticoagulant (OAC) groups while censoring for medication cessation.

RESULTS

We identified 6052 obese patients on apixaban, 4233 on dabigatran, 4309 on rivaroxaban, and 13,417 on warfarin (mean age 66.7 years, 91% males, 80.4% whites). At baseline patients on apixaban had the lowest glomerular filtration rate and highest rates of previous stroke and MI compared to other OACs. Among patients with weight ≥ 120 kg and those with BMI > 40 kg/m², all DOACs were associated with lower risk of any hemorrhage, hemorrhagic stroke, and gastrointestinal (GI) bleeding. Patients with BMI > 40 kg/m² treated with DOACs had similar ischemic stroke risk with those on warfarin.

CONCLUSIONS

In this large cohort of obese Veterans Health Administration system patients, the use of DOACs resulted in lower hemorrhagic complications than warfarin while maintaining efficacy on ischemic stroke prevention.

Healthcare resource utilization and costs of rivaroxaban versus warfarin among non-valvular atrial fibrillation (NVAF) patients with obesity in a US population

AIM

To assess the real-world healthcare resource utilization (HRU) and costs of patients with non-valvular atrial fibrillation (NVAF) and obesity newly initiated on rivaroxaban or warfarin in the US.

METHODS

This retrospective study used IQVIA PharMetrics Plus data (01/2010-09/2019) to evaluate patients (≥18 years) with NVAF and obesity (body mass index ≥30 kg/m²) initiated on rivaroxaban or warfarin (on or after 01/2013). Inverse probability of treatment weighting (IPTW) was used to adjust for confounding between cohorts. HRU and costs were assessed post-treatment initiation. Weighted cohorts were compared using Poisson regression models and cost differences, with 95% confidence intervals (CIs) and p values generated using non-parametric bootstrap procedures.

RESULTS

After IPTW, 10,555 and 5,080 patients were initiated on rivaroxaban and warfarin, respectively (mean age: 59 years). At 12 months follow-up, the rivaroxaban cohort had lower all-cause HRU, including fewer hospitalizations (rate ratio [RR]: 0.80, 95% CI: 0.74, 0.87), emergency room visits (RR: 0.89, 95% CI: 0.83, 0.97), and outpatient visits (RR: 0.72, 95% CI: 0.69, 0.77; all p < .05). Medical costs were also reduced in the rivaroxaban cohort (mean difference: -$6,759, 95% CI: -$9,814, -$3,311) due to reduced hospitalization costs (mean difference: -$5,967, 95% CI: -$8,721, -$3,327), resulting in lower total all-cause healthcare costs compared to the warfarin cohort (mean difference: -$4,579, 95% CI: -$7,609, -$1,052; all p < .05). The rivaroxaban cohort also had lower NVAF-related HRU and medical costs driven by lower hospitalization at 12 months post-treatment initiation. HRU and cost reductions associated with rivaroxaban persisted up to 36 months of follow-up.

LIMITATIONS

Claims data may have contained inaccuracies and obesity was classified based on ICD diagnosis codes given that patient BMI values were not available.

CONCLUSIONS

Rivaroxaban was associated with reduced HRU and costs compared to warfarin among NVAF patients with obesity in a real-world US setting.

Use of direct-acting oral anticoagulants in solid organ transplantation: A systematic review

The use of direct-acting oral anticoagulants (DOACs) has increased secondary to the mounting evidence for comparable efficacy and potentially superior safety to vitamin K antagonists (VKAs) in the general population. However, insufficient data regarding DOAC use in solid organ transplant (SOT) recipients and numerous pharmacokinetic and pharmacodynamic considerations limit their use in this highly selected patient population. A systematic review of recent clinical evidence on the safety and efficacy of DOACs compared to VKAs in SOT recipients was conducted. Additional considerations including transplant-specific strategies for DOAC reversal and common pharmacokinetic/pharmacodynamic concerns were also reviewed. Although current evidence is limited to single-center retrospective analyses, DOACs, especially apixaban, appear to be a safe and effective alternative to VKAs for SOT recipients with stable graft function and without drug-drug interactions. Reliable data on DOAC reversal at the time of transplant surgery are lacking, and clinicians should consider idarucizumab, andexanet alfa, and other non-specific reversal agents on an individual patient basis. There is no evidence supporting deviations from the Food and Drug Administration labeling recommendations for DOAC dosing in the setting of drug-drug interactions, obesity, and renal function, especially in patients on hemodialysis.

Dosage of Anticoagulants in Obesity: Recommendations Based on a Systematic Review

Anticoagulants are frequently used as thromboprophylaxis and in patients with atrial fibrillation (AF) or venous thromboembolism (VTE). While obesity rates are reaching epidemic proportions worldwide, the optimal dosage for obese patients has not been established for most anticoagulants, including low-molecular-weight heparin (LMWH), non-vitamin K antagonist oral anticoagulants (NOAC), and pentasaccharides (fondaparinux). The aim of the present systematic review was to summarize the current knowledge and provide recommendations on dosage of LMWH, NOAC, and fondaparinux in obese patients (body mass index [BMI] ≥ 30 kg/m² or body weight ≥ 100 kg). Based on a systematic search in PubMed and Embase, a total of 72 studies were identified. For thromboprophylaxis with LMWH in bariatric surgery (n = 20 studies), enoxaparin 40 mg twice daily, dalteparin 5,000 IE twice daily, or tinzaparin 75 IU/kg once daily should be considered for patients with BMI ≥ 40 kg/m². For thromboprophylaxis with LMWH in nonbariatric surgery and in medical inpatients (n = 8 studies), enoxaparin 0.5 mg/kg once or twice daily or tinzaparin 75 IU/kg once daily may be considered in obese patients. For treatment with LMWH (n = 18 studies), a reduced weight-based dose of enoxaparin 0.8 mg/kg twice daily should be considered in patients with BMI ≥ 40 kg/m², and no dose capping of dalteparin and tinzaparin should be applied for body weight < 140 kg. As regards NOAC, rivaroxaban, apixaban, or dabigatran may be used as thromboprophylaxis in patients with BMI < 40 kg/m² (n = 4 studies), whereas rivaroxaban and apixaban may be administered to obese patients with VTE or AF, including BMI > 40 kg/m², at standard fixed-dose (n = 20 studies). The limited available evidence on fondaparinux (n = 3 studies) indicated that the treatment dose should be increased to 10 mg once daily in patients weighing > 100 kg.

Prescribing Pattern of Oral Anticoagulants in Patients With Obesity

Introduction:

There is limited efficacy and safety data for direct oral anticoagulants (DOACs) in patients with obesity, and it has been suggested to avoid DOACs in this patient population.

Objective:

Describe the prescribing pattern of oral anticoagulants in obese patients in an urban university setting and assess efficacy, safety, and adherence.

Methods:

Retrospective, cohort study in patients ≥18 years with a history of VTE and/or atrial fibrillation. Patients with a BMI >40 kg/m2 and/or weight >120 kilograms and a prescription for warfarin or a DOAC from August 25, 2014 until August 25, 2017 are included. The primary outcome is the number of warfarin or DOAC prescriptions. Secondary outcomes include thromboembolism and bleeding events. Patient adherence was evaluated using time in therapeutic range (TTR), adherence rate to clinic appointments, and medication possession ratio (MPR).

Results:

Of the 276 patients who met eligibility criteria, 158 (57.2%) were prescribed warfarin and 118 (42.8%) were prescribed a DOAC. There was no difference in the rate of stroke or recurrent VTE between groups (3.2% vs. 3.4%, p = 0.944). There was also no difference in the rate of bleeding between groups (16.1% vs. 17.8%, p = 0.707). The TTR for the warfarin group was 44.8 ± 23%, and appointment adherence was 78.6 ± 20%. The MPR for the DOAC group was 0.93 ± 0.24.

Conclusions:

Despite limited data in obese patients, DOACs are prescribed in this population. Results suggest no difference in safety and efficacy compared to warfarin, but barriers to quality anticoagulation may exist in this population.

Clinical Performance of Nonvitamin K Antagonist Oral Anticoagulants in Real-World Obese Patients with Atrial Fibrillation

The prevalence of both atrial fibrillation (AF) and obesity has steadily increased. Nonvitamin K antagonist oral anticoagulants (NOACs) have been shown to be more effective and safer than vitamin K antagonists (VKAs) for long-term stroke prevention in patients with nonvalvular AF. There are still limited data in the literature regarding performance of NOACs in obese patients with AF in the “real world.” The aim of our study was to compare the safety and effectiveness of NOACs versus well-controlled VKA therapy in obese AF patients in a “real-world” setting. Here, we have considered patients with AF and obesity (body mass index [BMI] > 30 kg/m2) on NOAC or VKA therapy included in the multicenter Atrial Fibrillation Research Database (NCT03760874). The occurrence of major bleedings (MBs) and thromboembolic events (composite of ischemic stroke, transient ischemic attack, and systemic embolism) was respectively considered primary safety and effectiveness outcomes. We identified 1,047 AF patients with obesity who received NOAC (n = 272) or VKA (n = 775) treatment. After propensity score matching analysis, 248 NOAC and 496 VKA recipients with similar clinical characteristics, including BMI (34.8 ± 3.4 in NOAC vs. 35.1 ± 3.8 in the VKA group; p = 0.50), were evaluated. The mean follow-up was 39 ± 7 months. The incidence rate of thromboembolic events was 1.10 per 100 person-years (0.67 in NOAC vs. 1.28 in the VKA group; hazard ratio [HR]: 0.52; 95% confidence interval [CI]: 0.22–1.22; p = 0.19). The incidence rate of MB was 1.9 per 100 person-years (1.1 in NOAC vs. 2.28 in the VKA group; HR: 0.46; 95% CI: 0.24–0.88; p = 0.04). The incidence rate of intracranial hemorrhage was 0.4 per 100 person-years (0.27 in NOAC vs. 0.47 in the VKA group; HR: 0.57; 95% CI: 0.12–2.73; p = 0.48). A positive net clinical benefit (NCB) of NOACs over VKAs was found (+0.91). Presence of anemia (HR: 1.75; p = 0.003) and concomitant use of antiplatelet drugs (HR: 2.41; p = 0.001) were found to be independent predictors of MB; moreover, age (HR: 1.65; p = 0.003) was an independent predictor of thromboembolic events. Our data support the hypothesis of safe and effective use of NOACs in patients with AF and obesity, justified by a statistically significant lower incidence of MB and a favorable NCB over VKAs.

Evaluation of characteristics and dosing regimens in patients with new or recurrent thrombosis on apixaban and rivaroxaban

Direct factor Xa inhibitors, such as apixaban and rivaroxaban, are widely used for treatment and prevention of venous thromboembolism; however, recent cases of therapeutic failure have been reported. Potential risk factors associated with therapeutic failure such as dose deviations outside of package labeling recommendations, and the use of direct factor Xa-specific inhibitor levels to guide clinical decision making continue to be areas of further investigation. Our study aimed to describe characteristics and dosing regimens in patients on apixaban or rivaroxaban who experienced a new or recurrent thrombosis. We performed a retrospective chart review on 190 patients on either apixaban or rivaroxaban presenting to our institution with new or breakthrough thromboembolism. Evaluation of prescribed anticoagulation regimens compared to package labeling recommendations, direct factor Xa inhibitor-specific anti-Xa levels, anticoagulation interruptions, use of parenteral bridge anticoagulation, final anticoagulation regimen disposition, and thrombosis-associated mortality were recorded. In patients presenting with breakthrough thromboembolism, 78% were on a regimen that matched package labeling recommendations. Anti-Xa levels were documented in 66 patients, the majority of which fell within institutional expected ranges at time of thrombosis. Therapy interruptions immediately prior to thrombosis were observed in 22% of patients and 21% of those patients received parenteral anticoagulation during interruption. Upon discharge, 46% of patients continued the same anticoagulation regimen with no changes. The mortality rate was 6%. In patients who present with new thromboembolism on apixaban or rivaroxaban, a thorough review of risks and benefits should be conducted to mitigate future risk of recurrent thrombosis.

How I treat obese patients with oral anticoagulants

Obesity has become a major threat to health worldwide. The prevalence of obesity is rapidly increasing, so much so that the World Health Organization has declared obesity as a global epidemic. Obesity is associated with multiple health problems, including venous thromboembolism and atrial fibrillation, both of which are treated with anticoagulation. However, obesity and treatments for obesity such as bariatric surgery can influence absorption, excretion, pharmacokinetics, and pharmacodynamics of various anticoagulants. This results in uncertainty regarding the best antithrombotic strategies in this population, particularly in the morbidly obese. In the recent years, several studies have attempted to investigate anticoagulation use in this population and provided more insight. Herein, we present 4 cases of anticoagulant use in the obese to illustrate the common challenges faced by clinicians and discuss our approach. Whenever possible, we provide a review of the literature and base our recommendations on the best available evidence.