INTRODUCTION

Warfarin is an established therapy to prevent ischemic stroke in patients with atrial fibrillation.1 Direct oral anticoagulants (DOACs) have emerged as alternative therapies due to favorable risk-benefit profiles compared with warfarin.1 Many patients with atrial fibrillation that meet guideline recommended criteria, especially Black and Hispanic patients, are not treated with anticoagulants.2 Several investigators have noted differences in oral anticoagulant treatment for atrial fibrillation in Black and Hispanic patients compared with their white counterparts.2, 3 However, a major shortcoming of these studies is the limited representation of patients of color.

We aimed to investigate oral anticoagulant use in a diverse population with atrial fibrillation.

METHODS

This is a retrospective epidemiological study of patients with non-valvular atrial fibrillation diagnosed at the Montefiore Medical Center (Bronx, New York) between January 1, 2015, and January 1, 2019 (n = 1674) in an outpatient setting. Patients older than 18 were included if they were prescribed anticoagulation, as per the 2019 ACC-AHA-HRS guidelines, with warfarin, apixaban, rivaroxaban, edoxaban, or dabigatran.1 Patients with valvular atrial fibrillation and stroke within 1 month of diagnosis were excluded. This study protocol was approved by the Montefiore Medical Center IRB.

Statistical analysis was performed with SPSS Version 25 (IBM SPSS Statistics for Windows). Differences in continuous and discrete variables were assessed using ANOVA test with Tukey’s post hoc analysis and chi-squared test, respectively. The relationship between race and anticoagulation use was analyzed using a logistic regression model, which controlled for prescriber, insurance status, baseline creatinine, and CHADSVASC score. A p value of < 0.05 was considered statistically significant.

RESULTS

A total of 1674 patients were included in the study. White, Black, Hispanic, and other racial/ethnic identifying subjects comprised 47.1%, 18%, 28.5%, and 6.5% of the patient population, respectively (Table 1). Overall, 62.4% of patients were Medicare recipients. Baseline creatinine was significantly higher among Black patients (1.4 ± 1.4) as compared with white patients (1.1 ± 1.1) (p = 0.001).

Table 1 Patient Cohort Demographic Information
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Overall, 73.3% of the patient cohort was prescribed DOAC for atrial fibrillation, whereas only 26.7% of patients were prescribed warfarin (Table 1). White patients were prescribed DOACs less often than Hispanic patients (70.2% vs. 78.8% p = 0.001, unadjusted OR 0.6, 95% CI 0.5–0.8; adjusted OR 0.6, 95% CI 0.4–0.8, p = 0.002) (Table 2).

Table 2 Logistic Regression Results
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There was no significant difference in the unadjusted and adjusted odds ratio comparing treatment differences between Hispanic and Black patients (unadjusted OR 0.7, 95% CI 0.5–1.0, p = 0.052; adjusted OR 0.8, 95% CI 0.6–1.2, p = 0.251) (Table 2).

Of all the prescriptions written by cardiologists, 74.8% were for DOACs, whereas all other physicians prescribed DOACs 67.7% of the time (Table 2) (unadjusted OR 1.4, 95% CI 1.1–1.8, p = 0.007; adjusted OR 1.6, 95% CI 1.2–2.2, p = 0.001).

DISCUSSION

Hispanic patients received DOACs more frequently than their white peers (Table 2). This is the largest study detailing initial anticoagulant treatment in a multiracial/ethnic cohort. It runs counter to findings of other investigators that demonstrated less frequent use of DOACs in patients of minority backgrounds as compared with white patients.2,3,4

In a study by Bhave et al., anticoagulant use was investigated in a population of 517,941 patients, comprised of 87% white patients, in which Black and Hispanic patients were less likely to receive oral anticoagulants.2 In contrast, patients of color made up more than half of our patient cohort. Our group previously demonstrated that ICD referral rates at the Montefiore Medical Center were not influenced by race, gender, or primary language.5

Of note, the majority of patients in our cohort were enrolled in Medicare. This differs from patient populations in other studies.3, 4 Dayoub et al. found that Medicare formularies have increased DOAC coverage as guidelines for anticoagulant use have been updated.6 Even though DOACs have become increasingly covered under Medicare prescription plans, they are available with restrictions such as patient cost sharing.6 As medical professionals continue to prescribe DOACs for atrial fibrillation, accessibility will remain an important issue for patients.