Racial Differences in Quality of Anticoagulation Therapy for Atrial Fibrillation (from the TREAT-AF Study)

Differences in quality of anticoagulation care delivery according to ethnoracial group in the United States: A scoping review

Anticoagulation therapy is standard for conditions like atrial fibrillation, venous thromboembolism, and valvular heart disease, yet it is unclear if there are ethnoracial disparities in its quality and delivery in the United States. For this scoping review, electronic databases were searched for publications between January 1, 2011 - March 30, 2022. Eligible studies included all study designs, any setting within the United States, patients prescribed anticoagulation for any indication, outcomes reported for ≥ 2 distinct ethnoracial groups. The following four research questions were explored: Do ethnoracial differences exist in 1) access to guideline-based anticoagulation therapy, 2) quality of anticoagulation therapy management, 3) clinical outcomes related to anticoagulation care, 4) humanistic/educational outcomes related to anticoagulation therapy. A total of 5374 studies were screened, 570 studies received full-text review, and 96 studies were analyzed. The largest mapped focus was patients' access to guideline-based anticoagulation therapy (88/96 articles, 91.7%). Seventy-eight articles made statistical outcomes comparisons among ethnoracial groups. Across all four research questions, 79 articles demonstrated favorable outcomes for White patients compared to non-White patients, 38 articles showed no difference between White and non-White groups, and 8 favored non-White groups (the total exceeds the 78 articles with statistical outcomes as many articles reported multiple outcomes). Disparities disadvantaging non-White patients were most pronounced in access to guideline-based anticoagulation therapy (43/66 articles analyzed) and quality of anticoagulation management (19/21 articles analyzed). Although treatment guidelines do not differentiate anticoagulant therapy by ethnoracial group, this scoping review found consistently favorable outcomes for White patients over non-White patients in the domains of access to anticoagulation therapy for guideline-based indications and quality of anticoagulation therapy management. No differences among groups were noted in clinical outcomes, and very few studies assessed humanistic or educational outcomes.

Racial and Ethnic Disparities in Stroke Prevention for Atrial Fibrillation

Racial and ethnic disparities in health care are well documented, although often underappreciated. In the setting of atrial fibrillation, stroke risk and severity may be higher in underrepresented ethnic populations. Additionally, the risk of bleeding is not uniform, and pharmacogenetics play an important role in anticoagulant therapy. In this narrative review, we discuss the complex issues surrounding stroke prevention in underrepresented ethnic groups with atrial fibrillation.

Association of Race and Ethnicity With Oral Anticoagulation and Associated Outcomes in Patients With Atrial Fibrillation: Findings From the Get With The Guidelines-Atrial Fibrillation Registry

Importance

Oral anticoagulation (OAC) is underprescribed in underrepresented racial and ethnic group individuals with atrial fibrillation (AF). Little is known of how differential OAC prescribing relates to inequities in AF outcomes.

Objective

To compare OAC use at discharge and AF-related outcomes by race and ethnicity in the Get With The Guidelines-Atrial Fibrillation (GWTG-AFIB) registry.

Design, Setting, and Participants

This retrospective cohort analysis used data from the GWTG-AFIB registry, a national quality improvement initiative for hospitalized patients with AF. All registry patients hospitalized with AF from 2014 to 2020 were included in the study. Data were analyzed from November 2021 to July 2022.

Exposures

Self-reported race and ethnicity assessed in GWTG-AFIB registry.

Main Outcomes and Measures

The primary outcome was prescription of direct-acting OAC (DOAC) or warfarin at discharge. Secondary outcomes included cumulative 1-year incidence of ischemic stroke, major bleeding, and mortality postdischarge. Outcomes adjusted for patient demographic, clinical, and socioeconomic characteristics as well as hospital factors.

Results

Among 69 553 patients hospitalized with AF from 159 sites between 2014 and 2020, 863 (1.2%) were Asian, 5062 (7.3%) were Black, 4058 (5.8%) were Hispanic, and 59 570 (85.6%) were White. Overall, 34 113 (49.1%) were women; the median (IQR) age was 72 (63-80) years, and the median (IQR) CHA2DS2-VASc score (calculated as congestive heart failure, hypertension, age 75 years and older, diabetes, stroke or transient ischemic attack, vascular disease, age 65 to 74 years, and sex category) was 4 (2-5). At discharge, 56 385 patients (81.1%) were prescribed OAC therapy, including 41 760 (74.1%) receiving DOAC. OAC prescription at discharge was lowest in Hispanic patients (3010 [74.2%]), followed by Black patients (3935 [77.7%]) Asian patients (691 [80.1%]), and White patients (48 749 [81.8%]). Black patients were less likely than White patients to be discharged while taking any anticoagulant (adjusted odds ratio, 0.75; 95% CI, 0.68-0.84) and DOACs (adjusted odds ratio, 0.73; 95% CI, 0.65-0.82). In 16 307 individuals with 1-year follow up data, bleeding risks (adjusted hazard ratio [aHR], 2.08; 95% CI, 1.53-2.83), stroke risks (aHR, 2.07; 95% CI, 1.34-3.20), and mortality risks (aHR, 1.22; 95% CI, 1.02-1.47) were higher in Black patients than White patients. Hispanic patients had higher stroke risk (aHR, 2.02; 95% CI, 1.38-2.95) than White patients.

Conclusions and Relevance

In a national registry of hospitalized patients with AF, compared with White patients, Black patients were less likely to be discharged while taking anticoagulant therapy and DOACs in particular. Black and Hispanic patients had higher risk of stroke compared with White patients; Black patients had a higher risk of bleeding and mortality. There is an urgent need for interventions to achieve pharmacoequity in guideline-directed AF management to improve overall outcomes.

Anticoagulation Control in Different Ethnic Groups Receiving Vitamin K Antagonist for Stroke Prevention in Atrial Fibrillation

Vitamin K antagonist such as warfarin reduces the risk of stroke in atrial fibrillation (AF) patients. Since warfarin has a narrow therapeutic index, its administration needs to be regularly monitored to avoid any adverse clinical outcomes such as stroke and bleeding. The quality of anticoagulation control with warfarin therapy can be measured by using time in therapeutic range (TTR). This review focuses on the prevalence of AF, quality of anticoagulation control (TTR) and adverse clinical outcome in AF patients within different ethnic groups receiving warfarin therapy for stroke prevention. A literature search was conducted in Embase and PubMed using keywords of “prevalence,” “atrial fibrillation,” “stroke prevention,” “oral anticoagulants,” “warfarin,” “ethnicities,” “race” “time in therapeutic range,” “adverse clinical outcome,” “stroke, bleeding.” Articles published by 1st February 2020 were included. Forty-one studies were included in the final review consisting of AF prevalence (n = 14 studies), time in therapeutic range (n = 18 studies), adverse clinical outcome (n = 9 studies) within different ethnic groups. Findings indicate that higher prevalence of AF but better anticoagulation control among the Whites as compared to other ethnicities. Of note, non-whites had higher risk of strokes and bleeding outcomes while on warfarin therapy. Addressing disparities in prevention and healthcare resource allocation could potentially improve AF-related outcomes in minorities.

Direct Oral Anticoagulant Adherence of Patients With Atrial Fibrillation Transitioned from Warfarin

Background

Reduced time in international normalized ratio therapeutic range (TTR) limits warfarin safety and effectiveness. In patients switched from warfarin to direct oral anticoagulants (DOACs), patient factors associated with low TTR could also increase risk of DOAC nonadherence. We investigated the relationship between warfarin TTR and DOAC adherence in warfarin‐treated patients with atrial fibrillation switched to DOAC.

Methods and Results

Using data from the Veterans Health Administration, we identified patients with atrial fibrillation switched from warfarin to DOAC (switchers) or treated with warfarin alone (non‐switchers). Logistic regression was used to evaluate association between warfarin TTR and DOAC adherence. We analyzed 128 605 patients (age, 71±9; 1.6% women; CHA₂DS₂‐VASc 3.5±1.6); 32 377 switchers and 96 228 non‐switchers. In 8016 switchers with international normalized ratio data to calculate 180‐day TTR before switch, TTR was low (median 0.45; IQR, 0.26–0.64). Patients with TTR <0.5 were more likely to be switched to DOAC (odds ratio [OR],1.68 [95% CI,1.62–1.74], P<0.0001), as were those with TTR <0.6 or TTR <0.7. Proportion of days covered ≥0.8 was achieved by 76% of switchers at 365 days. In low‐TTR individuals, proportion of days covered ≥0.8 was achieved by 70%, 72%, and 73% of switchers with TTR <0.5, 0.6, and 0.7, respectively. After multivariable adjustment, TTR <0.5 decreased odds of achieving 365‐day proportion of days covered ≥0.8 (OR, 0.49; 0.43–0.57, P<0.0001), with similar relationships for TTR <0.6 and TTR <0.7. In non‐switchers with TTR <0.5, long‐term TTR remained low.

Conclusions

In patients with atrial fibrillation switched from warfarin to DOAC, most achieved adequate DOAC adherence despite low pre‐switch TTRs. However, TTR trajectories remained low in non‐switchers. Patients with low warfarin TTR more consistently achieved treatment targets after switching to DOACs, although adherence‐oriented interventions may be beneficial.

Racial and Ethnic Differences in the Management of Atrial Fibrillation

Atrial fibrillation (AF) is the most common clinical arrhythmia, and it results in adverse outcomes and increased healthcare costs. Racial and ethnic differences in AF management, although recognized, are poorly understood. This review summarizes racial differences in AF epidemiology, genetics, clinical presentation, and management. In addition, it highlights the underrepresentation of racial and ethnic populations in AF clinical trials, especially trials focused on stroke prevention. Specific strategies are proposed for future research and initiatives that have potential to eliminate racial and ethnic differences in the care of patients with AF. Addressing racial and ethnic disparities in healthcare access, enrollment in clinical trials, resource allocation, prevention, and management will likely narrow the gaps in the care and outcomes of racial and ethnic minorities suffering from AF.

Association of Race and Ethnicity and Anticoagulation in Patients with Atrial Fibrillation Dually Enrolled in VA and Medicare: Effects of Medicare Part D on Prescribing Disparities

Background: Racial and ethnic disparities in anticoagulation exist in atrial fibrillation (AF) management in Medicare and the Veterans Health Administration (VA), but the influence of dual VA and Medicare enrollment is unclear. We compared anticoagulant initiation by race and ethnicity in dually enrolled patients and assessed the role of Medicare Part D enrollment on anticoagulation disparities. Methods: We identified patients with incident AF (2014-2018) dually enrolled in VA and Medicare. We assessed any anticoagulant initiation (warfarin or direct-acting oral anticoagulants, DOACs) within 90 days of AF diagnosis and DOAC use among anticoagulant initiators. We modeled anticoagulant initiation, adjusting for patient, provider, and facility factors, including main effects for race and ethnicity and Medicare Part D enrollment and an interaction term for these variables. Results: In 43,789 patients, 8.9% were Black, 3.6% Hispanic, and 87.5% White; 10.9% participated in Medicare Part D. Overall, 29,680 (67.8%) patients initiated any anticoagulant, of which 17,568 (59.2%) initiated DOACs. Lower proportions of Black (65.2%) than Hispanic (67.6%) or White (68.0%) patients initiated any anticoagulant (p= 0.001), and lower proportions of Black (56.3%) and Hispanic (55.9%) than White (59.6%) patients (p=0.001) initiated DOACs. Compared to White patients, Black patients had significantly lower initiation of any anticoagulant, adjusted odds ratio (aOR) 0.89; 95% CI 0.82-0.97. The aORs for DOAC initiation were significantly lower for Black (0.72; 95% CI, 0.65-0.81) and Hispanic (0.84; 95% CI, 0.70-1.00) than White patients.The interaction between race and ethnicity and Medicare Part D enrollment was non-significant for any anticoagulant (p=0.99) and DOAC (p=0.27) therapies. Conclusions: In dually enrolled VA and Medicare patients with AF, Black patients were less likely to initiate any anticoagulant and Black and Hispanic patients were less likely to initiate DOACs. Medicare Part D enrollment did not moderate the associations between race and ethnicity and anticoagulant therapies.

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.

Social determinants of atrial fibrillation

Atrial fibrillation affects almost 60 million adults worldwide. Atrial fibrillation is associated with a high risk of cardiovascular morbidity and death as well as with social, psychological and economic burdens on patients and their families. Social determinants - such as race and ethnicity, financial resources, social support, access to health care, rurality and residential environment, local language proficiency and health literacy - have prominent roles in the evaluation, treatment and management of atrial fibrillation. Addressing the social determinants of health provides a crucial opportunity to reduce the substantial clinical and non-clinical complications associated with atrial fibrillation. In this Review, we summarize the contributions of social determinants to the patient experience and outcomes associated with this common condition. We emphasize the relevance of social determinants and their important intersection with atrial fibrillation treatment and outcomes. In closing, we identify gaps in the literature and propose future directions for the investigation of social determinants and atrial fibrillation.

Patient-related factors associated with oral anticoagulation control: a population-based cohort study

OBJECTIVES

Time in therapeutic range (TTR) of ≥70% is a commonly used indicator of optimal anticoagulation control. This study aimed to determine the patterns and predictors of anticoagulation control in a population-based cohort of new users of warfarin.

METHODS

This was a retrospective cohort study. All adults (age ≥18 years) who had been newly initiated on warfarin therapy between January 2006 and March 2011were selected from administrative health databases. TTR was calculated using the Rosendaal method. Multivariable logistic regression models were used to identify patient-related factors associated with optimal TTR. Predictors of patients spending >30% of time above and below the therapeutic international normalised ratio (INR) range were also examined.

KEY FINDINGS

A total of 6032 patients were included in this study. The mean TTR was 54.1 ± 18.8%, and 82.3% of patients had subthreshold TTR (<70%). Compared with New Zealand Europeans, Māori and Pacific people had decreased odds of achieving optimal TTR and increased odds of spending >30% of time below the therapeutic INR range. Patients aged 65-74 years and 75 years or older had increased odds of achieving optimal TTR but decreased odds of spending >30% of time below the therapeutic INR range than those <65 years. Compared with those living in the least socioeconomically deprived areas, those living in the most deprived areas had decreased odds of achieving optimal TTR.

CONCLUSIONS

Anticoagulation control with warfarin is suboptimal in routine care in New Zealand. Age, ethnicity and deprivation index were significant predictors of TTR. It is important to ensure equitable access to appropriate, high-quality care for those living in deprived areas and those from ethnic minority groups.

Disparities in Anticoagulant Therapy Initiation for Incident Atrial Fibrillation by Race/Ethnicity Among Patients in the Veterans Health Administration System

IMPORTANCE

Atrial fibrillation is a common cardiac rhythm disturbance causing substantial morbidity and mortality that disproportionately affects racial/ethnic minority groups. Anticoagulation reduces stroke risk in atrial fibrillation, yet studies show it is underprescribed in racial/ethnic minority patients.

OBJECTIVE

To compare initiation of anticoagulant therapy by race/ethnicity for patients in the Veterans Health Administration (VA) system with atrial fibrillation.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included 111 666 patients within the VA system with incident atrial fibrillation between January 1, 2014, and December 31, 2018. Data were analyzed between December 1, 2019, and March 31, 2020.

EXPOSURES

Any anticoagulation was defined as receipt of warfarin or direct-acting oral anticoagulants, apixaban, dabigatran, edoxaban, or rivaroxaban.

MAIN OUTCOMES AND MEASURES

Initiation of any anticoagulation (or direct-acting oral anticoagulant therapy in those who initiated any anticoagulation) was examined within 90 days of an index atrial fibrillation diagnosis.

RESULTS

Our final cohort comprised 111 666 patients (109 386 men [98.0%] and 95 493 White patients [85.5%]; mean [SD] age, 72.9 [10.4] years). A total of 69 590 patients (62.3%) initiated any anticoagulant therapy, varying 10.5 percentage points by race/ethnicity (P < .001); initiation was lowest in Asian (52.2% [n = 676]) and Black (60.3% [n = 6177]) patients and highest in White patients (62.7% [n = 59 881]). Among anticoagulant initiators, 45 381 (65.2%) used direct-acting oral anticoagulants, varying 7.2 percentage points by race/ethnicity (P < .001); initiation was lowest in Hispanic (58.3% [n = 1470]), American Indian/Alaska Native (59.8% [n = 201]), and Black (60.9% [n = 3763]) patients and highest in White patients (66.0% [n = 39 502). Compared with White patients, the odds of initiating any anticoagulant therapy were significantly lower for Asian (adjusted odds ratio [aOR], 0.82; 95% CI, 0.72-0.94) and Black (aOR, 0.90; 95% CI 0.85-0.95) patients. Among initiators, the adjusted odds of direct-acting oral anticoagulant initiation were significantly lower for Hispanic (aOR, 0.79; 95% CI, 0.70-0.89), American Indian/Alaska Native (aOR, 0.75; 95% CI, 0.57-0.99), and Black (aOR, 0.74; 95% CI 0.69-0.80) patients.

CONCLUSIONS AND RELEVANCE

This cohort study found that in patients with incident atrial fibrillation managed in the VA system, race/ethnicity was independently associated with initiating any anticoagulant therapy and direct-acting oral anticoagulant use among anticoagulant initiators. Understanding the reasons for these treatment disparities is essential to improving equitable atrial fibrillation management and outcomes among racial/ethnic minority patients treated in the VA system.

Anticoagulation control in different ethnic groups receiving vitamin K antagonist therapy for stroke prevention in atrial fibrillation

BACKGROUND

Efficacy and safety of vitamin K antagonists (VKAs) is optimised in atrial fibrillation (AF) patients when the International Normalised Ratio (INR) is 2.0-3.0. Anticoagulation control comparing different ethnic groups is limited, although epidemiological studies suggest poorer INR control in non-white cohorts.

METHODS

VKA control was assessed retrospectively by time-in-the-therapeutic range (TTR) (Rosendaal method) and percentage INR-in-range (PINRR) in 991 White, Afro-Caribbean and South-Asian AF patients [overall mean (SD) age 71.6 (9.4) years; 55% male; mean (SD) CHA₂DS₂-VASc score 3.4 (1.6)] over a median (IQR) follow-up of 5.2 (3.2-7.0) years.

RESULTS

Compared to Whites, mean (SD) TTR and PINRR were significantly lower in South-Asians [TTR 67.9% vs. 60.5%; PINRR 58.8% vs. 51.6%, respectively] and Afro-Caribbeans [TTR 67.9% vs. 61.3%; PINRR 58.8% vs. 53.1%, respectively], despite similar INR monitoring intensity. Logistic regression revealed non-white ethnicity [OR 2.62; 95% Confidence Interval [CI] (1.67-4.10) and OR 3.47 (1.44-8.34)] and anaemia [OR 1.65 (1.00-2.70) and OR 6.27 (1.89-20.94)] as independent predictors of both TTR and PINRR < 70%, respectively. At follow-up, 329 (33.2%) patients experienced ≥1 major adverse clinical event. Cardiovascular hospitalisation was significantly higher among South-Asians (32.3%) compared to the Whites and Afro-Caribbeans (21.3% vs 25.6% respectively).

CONCLUSIONS

Ethnic disparities in quality of anticoagulation control are evident, with South-Asians and Afro-Caribbeans having poorer control compared to Whites, despite similar intensity INR monitoring. Non-white ethnicity remained the strongest independent predictor of poor TTR and PINRR. Interventions to improve anticoagulation control need to be implemented, particularly targeting ethnic minority patients.

Racial and Ethnic Differences in Response to Anticoagulation: A Review of the Literature

INTRODUCTION

Anticoagulants are among the most frequently prescribed medications in the United States. Racial and ethnic disparities in incidence and outcomes of thrombotic disorders are well-documented, but differences in response to anticoagulation are incompletely understood.

OBJECTIVE

The objective of this review is to describe the impact of race and ethnicity on surrogate and clinical end points related to anticoagulation and discuss racial or ethnic considerations for prescribing anticoagulants.

METHODS

A PubMed and MEDLINE search of clinical trials published between 1950 and May 2018 was conducted using search terms related to anticoagulation, specific anticoagulant drugs, race, and ethnicity. References of identified studies were also reviewed. English-language human studies on safety or efficacy of anticoagulants reporting data for different races or ethnicities were eligible for inclusion.

RESULTS

Seventeen relevant studies were identified. The majority of major trials reviewed for inclusion either did not include representative populations or did not report on the racial breakdown of participants. Racial differences in pharmacokinetics, dosing requirements, drug response, and/or safety end points were identified for unfractionated heparin, enoxaparin, argatroban, warfarin, rivaroxaban, and edoxaban.

CONCLUSIONS

Race appears to influence drug concentrations, dosing, or safety for some but not all direct oral anticoagulants. This information should be considered when selecting anticoagulant therapy for nonwhite individuals.

Racial Differences in Atrial Fibrillation Epidemiology, Management, and Outcomes

PURPOSE OF THE REVIEW

Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice and is associated with significant morbidity and healthcare cost. Most of the AF studies have predominantly included white population, with under-representation of minority population. In this review, we analyze the racial differences in epidemiology, disease awareness, risk factors, genetics, treatments, and outcomes of AF.

RECENT FINDINGS

African Americans have a higher prevalence of established AF risk factors but lower incidence and prevalence of AF than non-Hispanic whites. There is also a significant racial and ethnic differences in the prevalence of AF-related symptoms and the detection and awareness of AF. Non-white patients are afforded decreased use of rhythm control treatment strategies and anticoagulation both with warfarin and NOACs for stroke prevention. They are less likely to receive catheter ablation (CA) of AF, compared with non-Hispanic whites. AF in the minority racial and ethnic groups carries increased morbidity and mortality compared with white groups, especially in the black individuals with AF, who have been shown to have a lower QoL compared with their white or Hispanic counterparts. Minorities experience stroke more frequently than the whites which is usually more severe and disabling. There are significant racial differences in AF risk factors, manifestations, management, and outcomes. Recognition of these differences will aid in developing better preventive and treatment strategies for AF to decrease morbidity and mortality. In addition, this knowledge will enhance our understanding regarding the pathophysiology of AF including genetic predisposition.

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.

Site Variation and Outcomes for Antithrombotic Therapy in Atrial Fibrillation Patients After Percutaneous Coronary Intervention

Background:

Patients with atrial fibrillation (AF) treated with percutaneous coronary intervention (PCI) require multiple antithrombotic therapies. The optimal strategy is debated suggesting increased treatment variation. This study sought to characterize site-level variation in antithrombotic therapies in AF patients after PCI and determine the association with outcomes.

Methods:

Using the retrospective TREAT-AF study (The Retrospective Evaluation and Assessment of Therapies in AF) from the Veterans Health Administration, patients with newly diagnosed, nonvalvular AF between 2004 and 2015 followed by a PCI with a P2Y 12 -antagonist prescription were identified. Patients were grouped according to the therapy dispensed 7 days before until 30 days after the PCI: oral anticoagulation plus platelet inhibition (OAC+PI) or platelet inhibition only. A combined outcome of death, myocardial infarction, stroke, or major bleeding was assessed 1 year after PCI and Cox regression was performed to estimate hazard ratios.

Results:

Of 230 762 patients with newly diagnosed AF, 4042 (1.8%) underwent PCI and received a P2Y 12 -antagonist during the observation period (age, 67±9 years; CHA 2 DS 2 -VASc, 2.7±1.7; HAS-BLED, 2.6±1.2). Among these, 47% were prescribed OAC+PI, and 53% platelet inhibition only 7 days before until 30 days after the PCI. Across 63 sites, the use of OAC+PI ranged from 19% to 66%. Prescription of OAC+PI was independently associated with a reduction in the combined outcome of death, myocardial infarction, stroke, or major bleeding compared with platelet inhibition only (adjusted hazard ratio, 0.85; 95% CI, 0.73–0.99; P =0.033).

Conclusions:

In patients with established AF undergoing PCI, the use of OAC+PI varied substantially across sites in the 30 days post-PCI. Anticoagulation appeared to be underutilized but was associated with improved outcomes. Strategies to promote OAC+PI and minimize site variation may be useful, particularly in light of recent randomized trials.

The SAMe-TT2R2 Score Predicts Warfarin Control in an Australian Population with Atrial Fibrillation

Background: Warfarin requires regular monitoring with the time in therapeutic range (TTR), a common indicator of control and TTR > 70% is indicative of efficient anticoagulation. The SAMe-TT₂R₂ (sex, age, medical history, treatment, tobacco use, race) model has been utilised as a predictor of warfarin control, with a score ≥ 2 indicative of poor control. However, it has been suggested that race may be over-represented in this model. To date, no Australian studies have applied this model, possibly because race is not routinely recorded. Therefore, the aim of this study was to apply the SAMe-TT₂R₂ model in an Australian population on warfarin managed by both a warfarin care program (WCP) and general practitioner (GP). Methods: Retrospective data was collected for patients receiving warfarin via a WCP in Queensland and whilst being managed by a GP. Patient data was used to calculate the SAMe-TT₂R₂ score and the TTR for each patient. Mean TTR was used for analysis and comparison with the categorised SAMe-TT₂R₂ score. Results: Of the 3911 patients managed by a WCP, there was a significantly lower mean TTR for patients with a SAMe-TT₂R₂ score ≥ 2 compared to 0–1 (78.6 ± 10.7% vs. 80.9 ± 9.5%, p < 0.0001). Of these patients, 200 were analysed whilst managed by a GP and the categorised SAMe-TT₂R₂ score did not result in a statistically different mean TTR (69.3 ± 16.3% with 0–1 vs. 63.6 ± 15.0% with ≥2, p = 0.089), but a score ≥2 differentiated patients with a TTR less than 65%. Conclusions: The SAMe-TT₂R₂ model differentiated Australian patients with reduced warfarin control, despite the exclusion of race. In Australia, the SAMe-TT₂R₂ score could assist clinicians in identifying Australian patients who may obtain reduced warfarin control and benefit from additional interventions such as a dedicated WCP.

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.

Association of insurance type with receipt of oral anticoagulation in insured patients with atrial fibrillation: A report from the American College of Cardiology NCDR PINNACLE registry

BACKGROUND

It is poorly understood whether insurance type may be a major contributor to the underuse of oral anticoagulation (OAC) among patients with atrial fibrillation (AF), particularly for novel oral anticoagulants (NOACs).

METHODS

We performed a retrospective cohort registry study of patients with insurance, AF, CHA₂DS₂-VASc ≥2, and at least one outpatient encounter recorded in the ACC NCDR's PINNACLE Registry between January 1, 2011 and December 31, 2014. We used hierarchical regression, adjusting for patient characteristics and clustering by physician, to evaluate the association of insurance type (Private, Military, Medicare, Medicaid, Other) with receipt of OAC (any OAC, warfarin, or NOAC).

RESULTS

In 363,309 patients (age 75±10; 48% female), we found a significant difference in proportions of OAC and NOAC prescription across insurance types (OAC: Military 53%, Private 53%, Medicare 52%, Other 41%, Medicaid 41%, P<.001; NOAC: Military 24%, Private 19%, Medicare 17%, Other 17%, Medicaid 8%, P<.001). After adjustment for patient characteristics and facility, private, Medicaid, and other insurance were independently associated with a lower odds of OAC prescription relative to Medicare, but military insured patients were not significantly different. After adjustment, military and private insurance were independently associated with a higher odds of NOAC prescription relative to Medicare, while Medicaid and other insurance were associated with a lower odds of NOAC prescription.

CONCLUSIONS

In a contemporary US AF population, there was significant variation of OAC prescription across insurance plans, with the highest among private and Medicare insured patients. These differences may indicate that insurance plan, and its associated pharmacy benefits, affect the pace of diffusion of new therapies.

Use of the SAMe-TT2R2 score to predict anticoagulation control in atrial fibrillation and venous thromboembolism patients receiving vitamin K antagonists: A review

Identifying patients who are likely to achieve and maintain a therapeutic international normalized ratio when prescribed a vitamin K antagonist for stroke prevention in atrial fibrillation (AF) and venous thromboembolism (VTE) is challenging. The SAMe-TT₂R₂ score was developed on the basis of common clinical factors that can highlight patients who may be unable to achieve and maintain good anticoagulation control and for whom a "trial of warfarin" would be inadvisable. This review summarizes the main published prospective and retrospective studies that have validated the SAMe-TT₂R₂ score in patients with AF and VTE treated with a vitamin K antagonist and how the SAMe-TT₂R₂ score could aid clinical decision making; 19 studies were included. Taken together, validation studies suggest that the SAMe-TT₂R₂ score is able to predict good or poor anticoagulation control in patients with AF and VTE, although data on patients with VTE are limited (3 studies). The available evidence suggests that the SAMe-TT₂R₂ score may be a useful tool to aid clinical decision making for oral anticoagulants in patients with AF and VTE.

Clinical Prediction Model for Time in Therapeutic Range While on Warfarin in Newly Diagnosed Atrial Fibrillation

Background

Though warfarin has historically been the primary oral anticoagulant for stroke prevention in newly diagnosed atrial fibrillation (AF), several new direct oral anticoagulants may be preferred when anticoagulation control with warfarin is expected to be poor. This study developed a prediction model for time in therapeutic range (TTR) among newly diagnosed AF patients on newly initiated warfarin as a tool to assist decision making between warfarin and direct oral anticoagulants.

Methods and Results

This electronic medical record–based, retrospective study included newly diagnosed, nonvalvular AF patients with no recent warfarin exposure receiving primary care services through a large healthcare system in rural Pennsylvania. TTR was estimated as the percentage of time international normalized ratio measurements were between 2.0 and 3.0 during the first year following warfarin initiation. Candidate predictors of TTR were chosen from data elements collected during usual clinical care. A TTR prediction model was developed and temporally validated and its predictive performance was compared with the SAMe‐TT₂R₂ score (sex, age, medical history, treatment, tobacco, race) using R² and c‐statistics. A total of 7877 newly diagnosed AF patients met study inclusion criteria. Median (interquartile range) TTR within the first year of starting warfarin was 51% (32, 67). Of 85 candidate predictors evaluated, 15 were included in the final validated model with an R² of 15.4%. The proposed model showed better predictive performance than the SAMe‐TT₂R₂ score (R²=3.0%).

Conclusions

The proposed prediction model may assist decision making on the proper mode of oral anticoagulant among newly diagnosed AF patients. However, predicting TTR on warfarin remains challenging.

Prediction Score for Anticoagulation Control Quality Among Older Adults

Background

Time in the therapeutic range (TTR) is associated with the effectiveness and safety of vitamin K antagonist (VKA) therapy. To optimize prescribing of VKA, we aimed to develop and validate a prediction model for TTR in older adults taking VKA for nonvalvular atrial fibrillation and venous thromboembolism.

Methods and Results

The study cohort comprised patients aged ≥65 years who were taking VKA for atrial fibrillation or venous thromboembolism and who were identified in the 2 US electronic health record databases linked with Medicare claims data from 2007 through 2014. With the predictors identified from a systematic review and clinical knowledge, we built a prediction model for TTR, using one electronic health record system as the training set and the other as the validation set. We compared the performance of the new models to that of a published prediction score for TTR, SAMe‐TT₂R₂. Based on 1663 patients in the training set and 1181 in the validation set, our optimized score included 42 variables and the simplified model included 7 variables, abbreviated as PROSPER (Pneumonia, Renal dysfunction, Oozing blood [prior bleeding], Staying in hospital ≥7 days, Pain medication use, no Enhanced [structured] anticoagulation services, Rx for antibiotics). The PROSPER score outperformed SAMe‐TT₂R₂ when predicting both TTR ≥70% (area under the receiver operating characteristic curve 0.67 versus 0.55) and the thromboembolic and bleeding outcomes (area under the receiver operating characteristic curve 0.62 versus 0.52).

Conclusions

Our geriatric TTR score can be used as a clinical decision aid to select appropriate candidates to receive VKA therapy and as a research tool to address confounding and treatment effect heterogeneity by anticoagulation quality.

Warfarin Pharmacogenomics in Diverse Populations

Genotype-guided warfarin dosing algorithms are a rational approach to optimize warfarin dosing and potentially reduce adverse drug events. Diverse populations, such as African Americans and Latinos, have greater variability in warfarin dose requirements and are at greater risk for experiencing warfarin-related adverse events compared with individuals of European ancestry. Although these data suggest that patients of diverse populations may benefit from improved warfarin dose estimation, the vast majority of literature on genotype-guided warfarin dosing, including data from prospective randomized trials, is in populations of European ancestry. Despite differing frequencies of variants by race/ethnicity, most evidence in diverse populations evaluates variants that are most common in populations of European ancestry. Algorithms that do not include variants important across race/ethnic groups are unlikely to benefit diverse populations. In some race/ethnic groups, development of race-specific or admixture-based algorithms may facilitate improved genotype-guided warfarin dosing algorithms above and beyond that seen in individuals of European ancestry. These observations should be considered in the interpretation of literature evaluating the clinical utility of genotype-guided warfarin dosing. Careful consideration of race/ethnicity and additional evidence focused on improving warfarin dosing algorithms across race/ethnic groups will be necessary for successful clinical implementation of warfarin pharmacogenomics. The evidence for warfarin pharmacogenomics has a broad significance for pharmacogenomic testing, emphasizing the consideration of race/ethnicity in discovery of gene-drug pairs and development of clinical recommendations for pharmacogenetic testing.

Impact of Baseline Stroke Risk and Bleeding Risk on Warfarin International Normalized Ratio Control in Atrial Fibrillation (from the TREAT-AF Study)

Warfarin prevents stroke and prolongs survival in patients with atrial fibrillation and flutter (AF, collectively) but can cause hemorrhage. The time in international normalized ratio (INR) therapeutic range (TTR) mediates stroke reduction and bleeding risk. This study sought to determine the relation between baseline stroke, bleeding risk, and TTR. Using data from The Retrospective Evaluation and Assessment of Therapies in Atrial Fibrillation (TREAT-AF) retrospective cohort study, national Veterans Health Administration records were used to identify patients with newly diagnosed AF from 2003 to 2012 and subsequent initiation of warfarin. Baseline stroke and bleeding risk was determined by calculating CHA₂DS₂-VASc and HAS-BLED scores, respectively. Main outcomes were first-year and long-term TTR and INR monitoring rate. In 167,190 patients, the proportion of patients with TTR (>65%) decreased across increasing strata of CHA₂DS₂-VASc and HAS-BLED. After covariate adjustment, odds of achieving TTR >65% were significantly associated with high CHA₂DS₂-VASc or HAS-BLED score. INR monitoring rate was similar across risk strata. In conclusion, increased baseline stroke and bleeding risk is associated with poor INR control, despite similar rates of INR monitoring. These findings may paradoxically limit warfarin's efficacy and safety in high-risk patients and may explain observed increased bleeding and stroke rates in this cohort.

Racial/ethnic differences in atrial fibrillation symptoms, treatment patterns, and outcomes: Insights from Outcomes Registry for Better Informed Treatment for Atrial Fibrillation Registry

BACKGROUND

Significant racial/ethnic differences exist in the incidence of atrial fibrillation (AF). However, less is known about racial/ethnic differences in quality of life (QoL), treatment, and outcomes associated with AF.

METHODS

Using data from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation, we compared clinical characteristics, QoL, management strategies, and long-term outcomes associated with AF among various racial/ethnic groups.

RESULTS

We analyzed 9,542 participants with AF (mean age 74 ± 11 years, 43% women, 91% white, 5% black, 4% Hispanic) from 174 centers. Compared with AF patients identified as white race, patients identified as Hispanic ethnicity and those identified as black race were younger, were more often women, and had more cardiac and noncardiac comorbidities. Black patients were more symptomatic with worse QoL and were less likely to be treated with a rhythm control strategy than other racial/ethnic groups. There were no significant racial/ethnic differences in CHA2DS2-VASc stroke or ATRIA bleeding risk scores and rates of oral anticoagulation use were similar. However, racial and ethnic minority populations treated with warfarin spent a lower median time in therapeutic range of international normalized ratio (59% blacks vs 68% whites vs 62% Hispanics, P < .0001). There was no difference in long-term outcomes associated with AF between the 3 groups at a median follow-up of 2.1 years.

CONCLUSION

Relative to white and Hispanic patients, black patients with AF had more symptoms, were less likely to receive rhythm control interventions, and had lower quality of warfarin management. Despite these differences, clinical events at 2 years were similar by race and ethnicity.