Review of race/ethnicity in non vitamin K antagonist oral anticoagulants clinical trials

The Efficacy and Safety of NOAC in Very Elderly Atrial Fibrillation Patients: Data From the Korean National Health Insurance Cohort Registry

BACKGROUND AND OBJECTIVES

We investigated the clinical benefit of anticoagulation with non-vitamin K antagonist oral anticoagulant (NOAC) in very elderly atrial fibrillation (AF) patients through national healthcare insurance registry.

METHODS

Clinical data was acquired from the National Health Insurance Service of south Korea. Medical records of 862,935 patients who were diagnosed with AF from 2015 to 2020 were collected for analysis. Patients under the age of 85, prior history of intracranial hemorrhage, gastrointestinal bleeding and prior prescription days of aspirin, warfarin or NOAC exceeding 90 along with follow up period less than 90 days were excluded.

RESULTS

A total of 10,625 patients were eligible for analysis. Patients with oral anticoagulant (hazard ratio [HR], 0.60, 95% confidence interval [CI], 0.53-0.69, p<0.001) showed higher efficacy regarding cerebrovascular accident (CVA) compared to aspirin (HR, 0.84, 95% CI, 0.74-0.95, p=0.008) and no treatment group. Individual comparison of NOAC and aspirin via propensity score matching showed that patients with NOAC (HR, 0.71, 95% CI, 0.61-0.85, p<0.001) showed higher event free survival regarding CVA compared to aspirin. Bleeding risk was also higher for NOAC (HR, 1.28, 95% CI, 1.07-1.56, p=0.006) group but did not result in commensurate increase in mortality (HR, 0.60, 95% CI, 0.45-0.81, p<0.001).

CONCLUSIONS

Anticoagulation with NOAC in very elderly patient showed higher event free survival regarding CVA. Despite having higher event rate of bleeding, eventual death was lower for NOAC.

Edoxaban for the treatment of hypercoagulability and cerebral thromboembolism associated with cancer: A randomized clinical trial of biomarker targets

BACKGROUND

This study aimed compare efficacy of edoxaban and enoxaparin upon biomarkers of hypercoagulability in patients with cancer-related embolic stroke of undetermined source (ESUS).

METHODS

In this open-label, randomized, pilot trial, patients with cancer-related ESUS within 30 days of diagnosis were randomly assigned (1:1) to receive edoxaban (60 mg once daily) or enoxaparin (1 mg/kg twice daily) for 90 days. The primary endpoint was interval change of serum D-dimer level between days 0 and 7. The secondary endpoints were microembolic signals detected by transcranial Doppler at 7 and 90 days, the modified Rankin scale score, and stroke recurrence during 90 days. Safety outcomes included major bleeding and all-cause death at 90 days.

RESULTS

Of 303 patients with ischemic stroke and cancer, 40 fully met enrollment criteria and were randomized. Baseline D-dimer levels were numerically higher in the edoxaban group (22.9 ± 15.9 μg/mL vs 16.9 ± 16.9 μg/mL). D-dimer level change (%) between days 0 and 7 was similar in the two groups (53.2 ± 25.7 vs 52.2 ± 52.0; P = 0.11). Microembolic signals were detected in 41.1% and 43.8% at baseline, 41.2% and 42.9% at day 7, and 25.0% and 28.6% at day 90 in the edoxaban and enoxaparin groups, respectively. Non-significantly higher major bleeding (35.0% vs 10.0%, P = 0.06) and 90-day mortality (40.0% vs 25.0%, P = 0.31) were noted in the edoxaban group.

CONCLUSION

Edoxaban and enoxaparin were comparable with respect to the biomarkers of hypercoagulability and cerebral thromboembolism. Larger trials are warranted to compare effects of edoxaban and enoxaparin upon recurrent stroke and major bleeding in patients with cancer-related ESUS.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT03570281 (https://clinicaltrials.gov/ct2/show/NCT03570281).

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

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

Percutaneous left atrial appendage occlusion: A review of current devices, clinical evidence, patient selection, and post procedural antithrombotic management

Stroke is a major driver of increased morbidity and mortality in patients with non-valvular atrial fibrillation (NVAF). While systemic oral anticoagulation (OAC) continues to be the mainstay for stroke reduction therapy in patients with NVAF, several barriers prevent the sustained long-term use of OAC, including increased risk of bleeding, non-compliance, cost, drug-drug interactions, and the need for ongoing laboratory testing. Given the need for continued stroke reduction therapies in patients who are intolerant of or non-compliant with OAC, percutaneous left atrial appendage (LAA) occlusion (LAAO) has emerged as a nonpharmacologic alternative to OAC. The development of percutaneous LAAO techniques is based on data suggesting that more than 90% of thrombi in patients with NVAF originate in the LAA. Two percutaneous LAAO devices are currently in widespread clinical use: Watchman (United States and Europe) and the Amplatzer type of devices (Europe); randomized trial data exist only for the Watchman device. Multiple randomized and nonrandomized trials and registries have demonstrated the safety and effectiveness of LAAO in patients who are suitable for short-term anticoagulation using a variety of post-procedural antithrombotic strategies. Ongoing randomized clinical trials on LAAO are focused on OAC-ineligible patients to compare efficacy of LAAO devices against a multitude of antithrombotic options. This review aims to discuss the rationale and evidence for LAAO and post procedural antithrombotic strategies and opportunities for research examination. In addition, we discuss the need for continued investigation of LAAO in populations not well represented in clinical trials or registries, including women, older patients, and underrepresented racial and ethnic groups.

Rivaroxaban versus warfarin for treatment and prevention of recurrence of venous thromboembolism in African American patients: a retrospective cohort analysis

Background

African Americans are under-represented in trials evaluating oral anticoagulants for the treatment of acute venous thromboembolism (VTE). The aim of this study was to evaluate the effectiveness and safety of rivaroxaban versus warfarin for the treatment of VTE in African Americans.

Methods

We utilized Optum® De-Identified Electronic Health Record data from 11/1/2012–9/30/2018. We included African Americans experiencing an acute VTE during a hospital or emergency department visit, who received rivaroxaban or warfarin as their first oral anticoagulant within 7-days of the acute VTE event and had ≥1 provider visit in the prior 12-months. Differences in baseline characteristics between cohorts were adjusted using inverse probability-of-treatment weighting based on propensity scores (standard differences < 0.10 were achieved for all covariates). Our primary endpoint was the composite of recurrent VTE or major bleeding at 6-months. Three- and 12-month timepoints were also assessed. Secondary endpoints included recurrent VTE and major bleeding as individual endpoints. Cohort risk was compared using Cox regression and reported as hazard ratios (HRs) with 95% confidence intervals (CIs).

Results

We identified 2097 rivaroxaban and 2842 warfarin users with incident VTE. At 6-months, no significant differences in the composite endpoint (HR = 0.96, 95%CI = 0.75–1.24), recurrent VTE (HR = 1.02, 95%CI = 0.76–1.36) or major bleeding alone (HR = 0.93, 95%CI = 0.59–1.47) were observed between cohorts. Analysis at 3- and 12-months provided consistent findings for these endpoints.

Conclusions

In African Americans experiencing an acute VTE, no significant difference in the incidence of recurrent VTE or major bleeding was observed between patients receiving rivaroxaban or warfarin.

Race/Ethnicity and Sex-Related Differences in Direct Oral Anticoagulant Initiation in Newly Diagnosed Atrial Fibrillation: A Retrospective Study of Medicare Data

BACKGROUND

Atrial fibrillation (AF) is the most common heart rhythm disorder and is associated with a 5-fold increased risk of ischemic stroke. Racial/ethnic minorities and women with AF have higher rates of stroke compared to white individuals and men respectively. Oral anticoagulation reduces the risk of stroke, yet prior research has described racial/ethnic and sex-based variation in its use. We sought to examine the initiation of any oral anticoagulant (warfarin or direct-acting oral anticoagulants, DOACs) by race/ethnicity and sex in patients with incident, non-valvular AF. Further in those who initiated any anticoagulant, we examined DOAC vs. warfarin initiation by race/ethnicity and sex.

METHODS

We used claims data from a 5% sample of Medicare beneficiaries to identify patients with incident AF from 2012 to 2014, excluding those without continuous Medicare enrollment. We used logistic regression to assess the association between race/ethnicity (white, black, Hispanic), sex, and oral anticoagulant initiation (any, warfarin vs. DOAC), adjusting for sociodemographics, medical comorbidities, stroke and bleeding risk.

RESULTS

The cohort of 42,952 patients with AF included 17,935 women, 3282 blacks, and 1958 Hispanics. Overall OAC initiation was low (49.2% whites, 48.1% blacks, 47.5% Hispanics, 48.1% men, and 51.5% women). After adjusting, blacks (odds ratio (OR) 0.84; 95% CI, 0.78-0.91) were less likely than whites to initiate any oral anticoagulant with no difference observed between Hispanics and whites (OR 0.92; 95% CI, 0.83-1.01). Women were less likely than men to initiate any oral anticoagulant, OR 0.59 (95% CI 0.55-0.64). Among initiators of oral anticoagulation, DOAC use was low (35.8% whites, 29.3% blacks, 40.0% Hispanics, 41.6% men, and 42.4% women). After adjusting, blacks were less likely to initiate DOACs than whites, OR 0.75 (95% CI 0.66-0.85); the odds of DOAC initiation did not differ between Hispanic and white patients or between men and women.

CONCLUSION

In a national cohort of Medicare beneficiaries with newly-diagnosed AF, overall oral anticoagulant initiation was lower in blacks and women, with no difference observed by Hispanic ethnicity. Among oral anticoagulant initiators, blacks were less likely to initiate novel DOACs, with no differences identified by Hispanic ethnicity or sex. Identifying modifiable causes of treatment disparities is needed to improve quality of care for all patients with AF.

Association of Race/Ethnicity With Oral Anticoagulant Use in Patients With Atrial Fibrillation: Findings From the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II

Importance

Black and Hispanic patients are less likely than white patients to use oral anticoagulants for atrial fibrillation. Little is known about racial/ethnic differences in use of direct-acting oral anticoagulants (DOACs) for atrial fibrillation.

Objective

To assess racial/ethnic differences in the use of oral anticoagulants, particularly DOACs, in patients with atrial fibrillation.

Design, Setting, and Participants

This cohort study used data from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation II, a prospective, US-based registry of outpatients with nontransient atrial fibrillation 21 years and older who were followed up from February 2013 to July 2016. Data were analyzed from February 2017 to February 2018.

Exposures

Self-reported race/ethnicity as white, black, or Hispanic.

Main Outcomes and Measures

The primary outcome was use of any oral anticoagulant, particularly DOACs. Secondary outcomes included the quality of anticoagulation received and oral anticoagulant discontinuation at 1 year.

Results

Of 12 417 patients, 11 100 were white individuals (88.6%), 646 were black individuals (5.2%), and 671 were Hispanic individuals (5.4%) with atrial fibrillation. After adjusting for clinical features, black individuals were less likely to receive any oral anticoagulant than white individuals (adjusted odds ratio [aOR], 0.75 [95% CI, 0.56, 0.99]) and less likely to receive DOACs if an anticoagulant was prescribed (aOR, 0.63 [95% CI, 0.49-0.83]). After further controlling for socioeconomic factors, oral anticoagulant use was no longer significantly different in black individuals (aOR, 0.78 [95% CI, 0.59-1.04]); among patients using oral anticoagulants, DOAC use remained significantly lower in black individuals (aOR, 0.73 [95% CI, 0.55-0.95]). There was no significant difference between white and Hispanic groups in use of oral anticoagulants. Among patients receiving warfarin, the median time in therapeutic range was lower in black individuals (57.1% [IQR, 39.9%-72.5%]) and Hispanic individuals (51.7% [interquartile range {IQR}, 39.1%-66.7%]) than white individuals (67.1% [IQR, 51.8%-80.6%]; P < .001). Black and Hispanic individuals treated with DOACs were more likely to receive inappropriate dosing than white individuals (black patients, 61 of 394 [15.5%]; Hispanic patients, 74 of 409 [18.1%]; white patients, 1003 of 7988 [12.6%]; P = .01). One-year persistence on oral anticoagulants was the same across groups.

Conclusions and Relevance

After controlling for clinical and socioeconomic factors, black individuals were less likely than white individuals to receive DOACs for atrial fibrillation, with no difference between white and Hispanic groups. When atrial fibrillation was treated, the quality of anticoagulant use was lower in black and Hispanic individuals. Identifying modifiable causes of these disparities could improve the quality of care in atrial fibrillation.

Genetic determinants of dabigatran safety (CES1 gene rs2244613 polymorphism) in the Russian population: multi-ethnic analysis

This study was aimed to investigate the prevalence of the CES1 gene (c.1168-33A > C, rs2244613) polymorphism among 12 different ethnic groups living in Russia to provide a basis for future clinical studies concerning genetic determinants of dabigatran safety. The study involved 1630 apparently healthy, unrelated, and chronic medication-free volunteers of both genders from 12 different ethnic groups in Russia: 136 Russians, 90 Avars, 50 Dargins, 46 Laks, 120 Kabardians, 112 Balkars, 244 Ossetians, 206 Mari, 204 Mordvinians, 238 Chuvashes, 114 Buryats and 70 Nanays. Genotyping was performed by using real-time polymerase chain reaction-based methods. The allelic prevalence of the ethnic groups was compared with Caucasus population participating in the RE-LY study. Statistically significant differences for the following gene polymorphism were found between all ethnic groups and RE-LY participants. Based on obtained results, it can be assumed that patients of all ethnic groups living in Russia taking dabigatran have a lower risk of bleeding.

Racial and ethnic differences in the prevalence, management, and outcomes in patients with atrial fibrillation: A systematic review

Atrial fibrillation (AF) is the most common cardiac arrhythmia in the United States and is associated with increased morbidity, mortality, and health care expenditures. In this review, our aim was to assess the racial and ethnic differences in the epidemiology, management, and outcomes of patients with AF. A search of relevant studies from January 1, 2007, to December 30, 2017, was conducted in PubMed, EMBASE, and Web of Science and supplemented by manual searches of the bibliographies of retrieved articles. We identified 152 studies of which 64 were subsequently included. We found that underrepresented racial and ethnic groups have a higher prevalence of established risk factors associated with the development of AF but an overall lower incidence and prevalence of AF as compared with non-Hispanic whites. Moreover, racial and ethnic differences exist in detection, awareness, and AF-associated symptoms. Nonwhite populations also experience decreased use of rhythm control modalities and anticoagulation for stroke prevention. Lastly, among those with AF, underrepresented racial and ethnic groups had increased morbidity and mortality relative to white groups. Racial and ethnic differences exist in the prevalence, quality of life, management, and outcomes of individuals with AF; however, the mechanisms for these differences have yet to be fully elucidated. Racial and ethnic differences in AF warrant further analysis to understand the factors contributing to the differences in prevalence and management to ensure the delivery of high quality care that prevents stroke, reduces deaths, and decreases expenses associated with caring for underrepresented populations with AF.

Quality of anticoagulation control and hemorrhage risk among African American and European American warfarin users

OBJECTIVE

We evaluated whether percent time in target range (PTTR), risk of over-anticoagulation [international normalized ratio (INR)>4], and risk of hemorrhage differ by race. As PTTR is a strong predictor of hemorrhage risk, we also determined the influence of PTTR on the risk of hemorrhage by race.

PARTICIPANTS AND METHODS

Among 1326 warfarin users, PTTR was calculated as the percentage of interpolated INR values within the target range of 2.0-3.0. PTTR was also categorized as poor (PTTR<60%), good (60≤PTTR<70%), or excellent (PTTR≥70%) anticoagulation control. Over-anticoagulation was defined as INR more than 4 and major hemorrhages included serious, life-threatening, and fatal bleeding episodes. Logistic regression and survival analyses were carried out to evaluate the association of race with PTTR (≥60 vs. <60) and major hemorrhages, respectively.

RESULTS

Compared with African Americans, European Americans had higher PTTR (57.6 vs. 49.1%; P<0.0001) and were more likely to attain 60≤PTTR<70% (22.9 vs. 13.1%; P<0.001) or PTTR of at least 70% (26.9 vs. 18.2%; P=0.001). Older (>65 years) patients without venous thromboembolism indication and chronic kidney disease were more likely to attain PTTR of at least 60%. After accounting for clinical and genetic factors, and PTTR, African Americans had a higher risk of hemorrhage [hazard ratio (HR)=1.58; 95% confidence interval (CI): 1.04-2.41; P=0.034]. Patients with 60≤PTTR<70% (HR=0.62; 95% CI: 0.38-1.02; P=0.058) and PTTR of at least 70% (HR=0.27; 95% CI: 0.15-0.49; P<0.001) had a lower risk of hemorrhage compared with those with PTTR less than 60%.

CONCLUSION

Despite the provision of warfarin management through anticoagulation clinics, African Americans achieve a lower overall PTTR and have a significantly higher risk of hemorrhage. Personalized medicine interventions tailored to African American warfarin users need to be developed.