Body mass index predicts major bleeding risks in patients on warfarin

Relationship between body mass index and clinical events in patients with atrial fibrillation undergoing percutaneous coronary intervention

BACKGROUND

It is still unclear whether body mass index (BMI) affects bleeding and cardiovascular events in patients requiring oral anticoagulants (OAC) for atrial fibrillation (AF) and antiplatelet agents after percutaneous coronary intervention (PCI) for coronary artery disease (CAD). The aim of this study was to evaluate the relationship between BMI and clinical events in patients who underwent PCI under OAC therapy for AF.

METHOD

This was a multicenter, observational cohort study conducted at 15 institutions in Japan. AF patients who underwent PCI with drug-eluting stents for CAD were retrospectively and prospectively included. Patients were divided into the Group 1 (BMI <21.3 kg/m2) and the Group 2 (BMI ≥21.3 kg/m2) according to the first-quartile value of BMI. The primary endpoint was net adverse clinical events (NACE), a composite of major adverse cardiovascular events (MACE) and major bleeding events within one year after index PCI procedure.

RESULTS

In the 720 patients, 180 patients (25.0%) had BMI value <21.3 kg/m2. While the rates of NACE and MACE were significantly higher in the Group 1 than the counterpart (21.1% vs. 11.9%, p = 0.003 and 17.2% vs. 8.9%, p = 0.004), that of major bleeding did not differ significantly between the 2 groups (5.6% vs. 4.3%, p = 0.54). The cumulative rate of NACE and MACE was significantly higher in the Group 1 than the Group 2 (both log-rank p = 0.002), although that of major bleeding events was equivalent between the 2 groups (log-rank p = 0.41). In multivariable Cox regression analyses, while BMI value <21.3 kg/m2 was not associated with major bleeding events, that cut-off value was an independent predictor for increased NACE and MACE.

CONCLUSIONS

Among the patients undergoing PCI for CAD and requiring OAC for AF, BMI value was a useful indicator to predict major adverse clinical events.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Cardiac surgery in the morbidly obese

BACKGROUND

Obesity rates globally continue to rise and in turn the body mass index (BMI) of patients undergoing cardiac surgery is set to mirror this. Patients who are Class III obese (BMI ≥ 40) pose significant challenges to the surgical teams responsible for their care and are also at high risk of complications from surgery and even death. To improve outcomes in this population, interventions carried out in the preoperative, operative, and postoperative periods have shown promise. Despite this, there are no defined best practice national guidelines for perioperative management of obese patients undergoing cardiac surgery.

AIM

This review is aimed at clinicians and researchers in the field of cardiac surgery and aims to form a basis for the future development of clinical guidelines for the management of obese cardiac surgery patients.

METHODS

The PubMed database was utilized to identify relevant literature and strategies employed at various stages of the surgical journey were analyzed.

CONCLUSIONS

Data presented identified the benefits of preoperative respiratory muscle training, off-pump coronary artery bypass grafting where possible, and early extubation. Further randomized controlled trials are required to identify optimal operative and perioperative management strategies before the introduction of such guidance into clinical practice.

Do women with venous thromboembolism bleed more than men during anticoagulation? Data from the real-life, prospective START-Register

Background:

Venous thromboembolism (VTE) is a frequent and serious disease that requires immediate and long-term anticoagulant treatment, which is inevitably associated with a risk of bleeding complications. Some studies, though not all, reported a higher risk of bleeding in female patients treated with either old anticoagulants [vitamin k antagonists (VKAs)] or recent anticoagulants [direct oral anticoagulants (DOACs)]. Furthermore, analyses of clinical trials reported an abnormal vaginal bleeding in women of reproductive age treated with DOACs. This study aimed at comparing the risk of bleeding in an inception cohort of VTE women and men included in a prospective observational registry.

Methods:

Baseline characteristics and bleeding events occurring during anticoagulation in patients of both sexes, included in the START-Register after a first VTE, were analyzed.

Results:

In all, 1298 women were compared with 1290 men. Women were older and more often had renal diseases; their index events were often provoked (often by hormonal contraception and pregnancy), and more frequently presented as isolated pulmonary embolism (PE). The rate of bleeding was similar in women (2.9% patient-years) and men (2.1% patient-years), though it was higher when uterine bleeds were included (3.5% patient-years, p = 0.0141). More bleeds occurred in VKA- than DOAC-treated patients (6.4% versus 2.6%, respectively; p = 0.0013). At multivariate analysis, age ⩾ 75 years was associated with higher prevalence of bleeds.

Conclusion:

The occurrence of bleeding was not different between women and men during anticoagulation after VTE. Only after inclusion of vaginal/uterine bleeds, the rate of bleeding was higher in women. The incidence of bleeding was higher in women treated with VKAs.

Plain Language Summary

Influence of body mass index on clinical outcomes in venous thromboembolism: Insights from GARFIELD-VTE

BACKGROUND

There is limited information on the influence of body mass index (BMI) on clinical outcomes in patients with venous thromboembolism (VTE).

OBJECTIVES

Investigate the influence of BMI on baseline characteristics, treatment patterns, and 24-month outcomes in VTE patients.

METHODS

GARFIELD-VTE is a prospective, non-interventional study of 10 869 patients with objectively confirmed VTE. Patients were grouped according to BMI: <18.5 (underweight; n = 214); 18.5-24.9 (normal; n = 2866); 25.0-29.9 (overweight; n = 3326); ≥30 (obese; n = 3073).

RESULTS

Compared with patients with a normal BMI, obese patients were more frequently Caucasian (77.4% vs. 57.9%), treated in the outpatient setting (30.4% vs. 23.1%), and had previous VTE (17.5% vs. 11.7%). Active cancer was associated with lower BMI (underweight: 30.4%, normal: 13.5%, overweight: 9.4%, obese: 7.0%). At baseline, overweight and obese patients less often received parenteral therapy alone (16.7% and 14.4%) compared with those with an underweight or normal BMI (30.8% and 21.6%). Obese patients more commonly remained on anticoagulants for ≥2-years compared to those with a normal BMI (52.3% vs. 37.7%). After 24-months, the risk of all-cause mortality was lower in overweight and obese patients than in those with normal BMI (adjusted hazard ratio [95% CI]; 0.75 [0.63-0.89] and 0.59 [0.49-0.72], respectively). Underweight patients more often experienced major bleeding (2.45 [1.41-4.26]) and all-cause mortality (1.90 [1.43-2.53]) than patients with a normal BMI. Recurrent VTE was comparable among groups.

CONCLUSION

Underweight VTE patients have the highest risk of mortality and major bleeding. The risk of mortality in obese VTE patients is lower than that in VTE patients with a normal BMI.

Thrombosis and bleeding outcomes in the treatment of cerebral venous thrombosis in cancer

Background

There is a need for clinical outcome data of cerebral venous thrombosis (CVT) in cancer patients. We examined the recanalization, thrombosis recurrence and major bleeding during CVT treatment in a cancer exclusive adult population.

Methods

We performed a retrospective review of cancer associated CVT identified through an institutional data warehouse. The primary endpoint was radiological and comprised the evaluation of thrombus recanalization at 12 months. Secondary endpoints were clinical and included rates of bleeding complications and recurrence of CVT. Variables were compared across subgroups of study outcomes. The backward stepdown procedure was used to identify variables for the final logistic model regarding thrombosis and bleeding outcomes.

Results

The population included forty-five patients, slightly predominant of male adults (55.6%) with a median age of 54.5 years. Solid malignancies comprised 64.4% of cases. A total of 31 cases were treated with anticoagulation. CVT recanalization was documented in almost 60% of cases. The cerebral venous thrombosis recurrence or propagation rate at 12 months was 15.6%. Major bleeding complications were observed in 15 patients.

Conclusions

Our findings are suggestive of a narrow therapeutic index of anticoagulation in cancer-CVT. Careful monitoring of anticoagulation effect and bleeding complications are of utmost clinical relevance in cancer patients. Further larger and controlled studies are needed to confirm our observations.

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

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

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

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

Relationship between body mass index and outcomes in patients with atrial fibrillation treated with edoxaban or warfarin in the ENGAGE AF-TIMI 48 trial

AIMS

To investigate the relationship between body mass index (BMI) and outcomes in patients with atrial fibrillation (AF).

METHODS AND RESULTS

In the ENGAGE AF-TIMI 48 trial, patients with AF were randomized to warfarin (international normalized ratio 2.0-3.0) or edoxaban. The cohort (N = 21 028) included patients across BMI categories (kg/m2): underweight (<18.5) in 0.8%, normal (18.5 to <25) in 21.4%, overweight (25 to <30) in 37.6%, moderately obese (30 to <35) in 24.8%, severely obese (35 to <40) in 10.0%, and very severely obese (≥40) in 5.5%. In an adjusted analysis, higher BMI (continuous, per 5 kg/m2 increase) was significantly and independently associated with lower risks of stroke/systemic embolic event (SEE) [hazard ratio (HR) 0.88, P = 0.0001], ischaemic stroke/SEE (HR 0.87, P < 0.0001), and death (HR 0.91, P < 0.0001), but with increased risks of major (HR 1.06, P = 0.025) and major or clinically relevant non-major bleeding (HR 1.05, P = 0.0007). There was a significant interaction between sex and increasing BMI category, with lower risk of ischaemic stroke/SEE in males and increased risk of bleeding in women. Trough edoxaban concentration and anti-Factor Xa activity were similar across BMI groups >18.5 kg/m2, while time in therapeutic range for warfarin improved significantly as BMI increased (P < 0.0001). The effects of edoxaban vs. warfarin on stroke/SEE, major bleeding, and net clinical outcome were similar across BMI groups.

CONCLUSION

An increased BMI was independently associated with a lower risk of stroke/SEE, better survival, but increased risk of bleeding. The efficacy and safety profiles of edoxaban were similar across BMI categories ranging from 18.5 to >40.

[Diagnostic and therapeutic management of venous thromboembolic disease in obese patients]

Despite the high proportion of obese patients this population remains understudied in the field of venous thromboembolic disease (VTE). Obesity is a risk factor for pulmonary embolism and/or deep vein thrombosis, especially when it is associated with other risk factors for VTE. Currently there is no validated diagnostic algorithm for VTE in the population of obese patients. Moreover, imaging examinations can be of poor quality and inconclusive. In the prevention of VTE, data concerning obese patients are mainly based on low-level studies. Apart from the context of bariatric surgery, an adjustment of heparin doses according to the weight of the patient is proposed only on a case-by-case basis. According to the current guidelines, therapeutic fixed dose oral anticoagulants should not be prescribed for patients with weights exceeding 120kg or a body mass index>40kg/m². Heparin doses should be weight adjusted and monitored with anti-Xa activity. Anti vitamin K can be prescribed but require INR monitoring. Therefore, new studies specifically dedicated to obese patients are required in the field of VTE for better diagnostic and therapeutic management.

Rivaroxaban Versus Warfarin for Stroke Prevention and Venous Thromboembolism Treatment in Extreme Obesity and High Body Weight

Background: Limited clinical data exist describing the use of direct-acting oral anticoagulants (DOACs) in patients with body mass index (BMI) >40 kg/m2 or body weight >120 kg. Thus, DOAC therapy in this population remains controversial. Objectives: To investigate rivaroxaban as a safe and effective alternative to warfarin for venous thromboembolism (VTE) treatment and prevention of stroke in patients with atrial fibrillation identified as extremely obese or of high body weight. Methods: A retrospective chart review was performed at 2 academic medical centers in patients ≥18 years old and BMI >40 kg/m2 or weight >120 kg, newly initiated on warfarin or rivaroxaban for atrial fibrillation or VTE treatment. The primary end point was incidence of clinical failure, defined as VTE recurrence, stroke incidence, and mortality, within 12 months of initiation. Secondary end points included length of stay (LOS) and bleeding complications. Results: A total of 176 patients were included, with 84 and 92 patients in the rivaroxaban and warfarin arms, respectively. Clinical failure was lower in the rivaroxaban group but did not reach statistical significance when compared with warfarin (5% vs 13%; P = 0.06). LOS was significantly shorter in the rivaroxaban arm (2 days [1-3] vs 4 days [2-7], P < 0.0001). Percentage of bleeding complications was higher in the rivaroxaban arm but not statistically significant (8% vs 2%, P = 0.06). Conclusion and Relevance: Although not statistically significant, rivaroxaban trended toward a lower incidence of clinical failure while demonstrating a significantly shorter LOS when compared with warfarin for VTE treatment or atrial fibrillation in morbidly obese or high-body-weight patients.

Evaluation of the efficacy of direct oral anticoagulants (DOACs) in comparison to warfarin in morbidly obese patients

Purpose: There is limited clinical data evaluating anticoagulation with the direct oral anticoagulants (DOACs) in morbidly obese patients. We sought to examine the efficacy in preventing stroke or other systemic embolic events and safety of apixaban, dabigatran, and rivaroxaban, in comparison to warfarin in patients with either a body-mass index (BMI) over 40 kg/m2 and/or a weight over 120 kg.Methods: After approval from IRB, we collected retrospective data from our institution's records on 180 patients. We analyzed the rates of stroke and systemic embolic events as defined as ischemic stroke, pulmonary embolism (PE), deep vein thrombosis (DVT), and myocardial infarction (MI) as well as major bleeding in morbidly obese patients receiving apixaban, dabigatran, or rivaroxaban in comparison to warfarin for anticoagulation due to nonvalvular atrial fibrillation, postoperative thrombus prophylaxis, or DVT/PE treatment and/or reduction in risk for recurrence.Results: The final analysis included 90 patients in both arms. Fifty-two percent (n = 41) of patients in the DOAC group were on apixaban therapy, 12% (n = 11) on dabigatran, and 37% (n = 33) on rivaroxaban. The average BMI and weight in the DOAC group were 46.7 kg/m2 and 139.3 kg, respectively. In the warfarin group, average BMI and weight were 45.8 kg/m2 and 135.9 kg, respectively. There were 11 patients who developed a stroke or thromboembolic event in the DOAC group and 10 in the warfarin group (OR 1.11, 95% confidence interval [CI] 0.45-2.78; p = 0.82). The events in the DOAC group consisted of three patients who developed ischemic stroke, three patients who developed DVTs, one who developed a PE, and four patients who developed MIs. There were two major bleeding events in the DOAC group and three events in the warfarin group (p = 0.65).Conclusions: Anticoagulation therapy with DOACs in morbidly obese patients may be a safe and effective alternative to warfarin for prevention of stroke or systemic embolic events. However, additional studies are necessary to confirm these findings.

Comparison of Two Different Techniques Of Warfarin Dosing Determination - A Chemometrics Study

A high prevalence of genetic polymorphisms increases sensitivity to warfarin therapy. In this study, we investigated 47 patients with effective long-term therapy by warfarin well-controlled by monitoring of International Normalised Ratio (INR). All patients were tested for gene polymorphisms VKORC1, CYP2C9*C2, and CYP2C9*C3, which were used for a dose calculation employing a program www.WarfarinDosing.org. The main goal was to investigate whether the warfarin doses determined by INR are in accordance with the doses calculated according to the pharmacogenetic algorithm. For this purpose, several chemometric tools, namely principal component analysis, cluster analysis, correlation analysis, correspondence analysis, Passing-Bablock regression, Bland-Altman method, descriptive statistics, and ANOVA were used. We also analysed the relationship between the dose of warfarin determined by INR and several constitutional and genetic factors. Statistically significant association between clinically optimized warfarin dose and indication for the treatment, age, and warfarin sensitivity determined by VKORC1, CYP2C9 gene polymorphisms were confirmed. Finally, we confirmed a good concordance between the INR determined warfarin doses and pharmacogenetic approach.

Effects of Obesity on Warfarin Reversal With Vitamin K

Phytonadione (vitamin K1, VK) is fat soluble and may be sequestered by adipose tissue, thus potentially altering drug distribution in obese patients requiring warfarin reversal. This single-center retrospective cohort study aimed to determine the effects of obesity (defined as body mass index [BMI] ≥ 30 kg/m²) on warfarin reversal following administration of VK in adult patients. The primary outcome was complete or partial warfarin reversal (defined as an international normalized ratio [INR] ≤ 2.0) within 72 hours post-VK administration. Of 688 identified patients, 215 were included in primary INR analysis. Mean BMIs for obese (n = 84) and nonobese (n = 131) patients were 37.3 and 24.3 kg/m² ( P < .001), and mean baseline INRs were 4.73 and 4.42 ( P = .534), respectively. Within 72 hours post-VK administration, 70% and 69% of the obese and nonobese groups, respectively, achieved complete or partial warfarin reversal ( P = .904). Multiple logistic regression determined baseline INR and concomitant fresh frozen plasma administration to be factors influencing warfarin reversal. These findings do not suggest obesity is significantly associated with a decreased likelihood of warfarin reversal within 72 hours post-VK administration.

Impact of BMI on Complications and Satisfaction in Patients With Papillary Thyroid Cancer and Lateral Neck Metastasis

BACKGROUND

This study investigates the effect of body mass index (BMI) on complications and satisfaction in patients who underwent thyroidectomy and lateral neck dissection.

METHODS

We retrospectively reviewed 386 patients with papillary thyroid cancer who underwent total thyroidectomy and lateral neck dissection between January 2013 and December 2016. We compared variables including population characteristics, subjective satisfaction, and complications in nonobese (BMI < 28.0 kg/m2) and obese (BMI ≥ 28.0 kg/m2) patients.

RESULTS

Obesity was associated with an increased risk of postoperative hemorrhage (POH) (P = .014), accessory nerve injury (P < .001), operative time (P < .001) and infection (P = .013). However, obese patients had higher subjective satisfaction and Vancouver Scar Scale (VSS) scores (P < .05).

CONCLUSIONS

Obesity was associated with increased risk of POH, injury of the SAN, and infection. Interestingly, we found that obese patients had higher subjective satisfaction and VSS scores.

Anticoagulation at the extremes of body weight: choices and dosing

INTRODUCTION

The landscape of therapeutic anticoagulation has changed dramatically over the past decade, with availability of direct oral anticoagulants (DOACs), which inhibit factor Xa or thrombin. However, the optimal anticoagulant agent and dosing strategy for patients at both extremes of body weight has not been established for any anticoagulant, including DOACs, vitamin K antagonists (VKA), and the various heparin options. Areas covered: This paper reviews available evidence to assist clinicians in prescribing of anticoagulation therapy at the extremes of body weight. Expert commentary: There are limited data to guide prescribing of all available anticoagulants at the extremes of weight and further research regarding efficacy and safety outcomes in these groups is required. Laboratory monitoring to guide dosing of traditional anticoagulants provides reassurance of 'predictable' efficacy. In contrast agents that are not routinely monitored by laboratory testing provide greater challenges. For example, underweight patients are at risk of receiving higher drug exposures of DOACs, whereas the use of fixed dose DOACs in obese patients may be associated with lower drug exposures.

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.

Impact of Body Mass Index and Genetics on Warfarin Major Bleeding Outcomes in a Community Setting

BACKGROUND

Several studies have demonstrated an association between body mass index (BMI) and warfarin therapeutic dose, but none evaluated the association of BMI with the clinically important outcome of major bleeding in a community setting. To address this evidence gap, we conducted a case-control study to evaluate the association between BMI and major bleeding risk among patients receiving warfarin.

METHODS

We used a case-control study design to evaluate the association between obesity (BMI >30.0 kg/m²) and major bleeding risk among 265 cases and 305 controls receiving warfarin at Group Health, an integrated healthcare system in Washington State. Multivariate logistic regression was used to adjust for potential confounders derived from health plan records and a self-report survey. In exploratory analyses we evaluated the interaction between genetic variants potentially associated with warfarin bleeding (CYP2C9, VKORC1, and CYP4F2) and obesity on the risk of major bleeding.

RESULTS

Overall, the sample was 55% male, 94% Caucasian, and mean age was 70 years. Cases and controls had an average of 3.4 and 3.7 years of warfarin use, respectively. Obese patients had significantly lower major bleeding risk relative to non-obese patients (odds ratio [OR] 0.60, 95% confidence interval [CI] 0.39-0.92). The OR was 0.56 (95% CI 0.35-0.90) in patients with ≥1 year of warfarin use, and 0.78 (95% CI 0.40-1.54) in patients with <1 year of warfarin use. An exploratory analysis indicated a statistically significant interaction between CYP4F2*3 genetic status and obesity (P = .049), suggesting a protective effect of obesity on the risk of major bleeding among those wild type for CYP4F2*3, but not among variants.

CONCLUSIONS

Our findings suggest that BMI is an important clinical factor in assessing and managing warfarin therapy. Future studies should confirm the major bleeding associations, including the interaction between obesity and CYP4F2*3 status identified in this study, and evaluate potential mechanisms.

Cerebrovascular Disease: Consequences of Obesity-Induced Endothelial Dysfunction

Despite the well-known global impact of overweight and obesity in the incidence of cerebrovascular disease, many aspects of this association are still inconsistently defined. In this chapter we aim to present a critical review on the links between obesity and both ischemic and hemorrhagic stroke and discuss its influence on functional outcomes, survival, and current treatments to acute and chronic stroke. The role of cerebrovascular endothelial function and respective modulation is also described as well as its laboratory and clinical assessment. In this context, the major contributing mechanisms underlying obesity-induced cerebral endothelial function (adipokine secretion, insulin resistance, inflammation, and hypertension) are discussed. A special emphasis is given to the participation of adipokines in the pathophysiology of stroke, namely adiponectin, leptin, resistin, apelin, and visfatin.

Thrombosis in the setting of obesity or inflammatory bowel disease

Obesity and inflammatory bowel disease (IBD) are systemic inflammatory disorders that predispose to arterial and venous thrombosis through similar prothrombotic mechanisms. Obesity and IBD are chronic risk factors that lead to a persistently elevated risk of thrombosis, although the thrombotic risk with IBD appears to wax and wane with disease severity. Because of the lack of high-quality evidence to guide management decisions, approaches to the prevention and treatment of thrombosis in patients with obesity or IBD are based on extrapolation from general guidelines for antithrombotic therapy. Obesity alters the pharmacokinetics of some anticoagulant drugs, and IBD patients present the added management challenge of having a high risk of gastrointestinal bleeding while taking anticoagulants. An extended duration of anticoagulant therapy is often recommended for obese or IBD patients with unprovoked venous thromboembolism unless there is a high risk of bleeding, although more data and better biomarkers are needed to determine whether anticoagulation can be safely stopped in a subset of IBD patients during remission of active disease. Most patients with obesity or IBD require thromboprophylaxis in conjunction with hospitalization or surgery, with adjustment of anticoagulant dosing in patients with severe obesity.

Thrombosis in the setting of obesity or inflammatory bowel disease

Obesity and inflammatory bowel disease (IBD) are systemic inflammatory disorders that predispose to arterial and venous thrombosis through similar prothrombotic mechanisms. Obesity and IBD are chronic risk factors that lead to a persistently elevated risk of thrombosis, although the thrombotic risk with IBD appears to wax and wane with disease severity. Because of the lack of high-quality evidence to guide management decisions, approaches to the prevention and treatment of thrombosis in patients with obesity or IBD are based on extrapolation from general guidelines for antithrombotic therapy. Obesity alters the pharmacokinetics of some anticoagulant drugs, and IBD patients present the added management challenge of having a high risk of gastrointestinal bleeding while taking anticoagulants. An extended duration of anticoagulant therapy is often recommended for obese or IBD patients with unprovoked venous thromboembolism unless there is a high risk of bleeding, although more data and better biomarkers are needed to determine whether anticoagulation can be safely stopped in a subset of IBD patients during remission of active disease. Most patients with obesity or IBD require thromboprophylaxis in conjunction with hospitalization or surgery, with adjustment of anticoagulant dosing in patients with severe obesity.