Racial differences and geographic variations in oral anticoagulation treatment among Medicare patients with non-valvular atrial fibrillation

PLoS One. 2024 Dec 12;19(12):e0314345. doi: 10.1371/journal.pone.0314345. eCollection 2024.

Abstract

Introduction: Use of oral anticoagulants (OACs) for stroke reduction in atrial fibrillation (AF) varies by race and geography within the United States. We seek to better understand the relationship between OAC underutilization, race, and US geography.

Methods: Patients with AF were selected from the US Centers for Medicare & Medicaid Services claims database from January 1, 2013, to December 31, 2016. The final population consisted of patients with 12 months of health plan enrollment before and after their index AF diagnosis, with a baseline CHAD2S2-VASc ≥2 and of either Black or White race (other races are underrepresented in the data). Among those with AF that met the inclusion criteria, patients who were prescribed warfarin or DOACs within 12 months after the index date were extracted. Each patient was assigned to a US county based on their 5-digit zip code and OAC use was stratified by race. Statistically significant differences were determined by student's t-test and chi-square.

Results: Of the 2,390,830 final patients, 94.1% were White and 5.9% were Black patients. Mean (SD) age and HASBLED scores were 78 (9) and 3.9 (1.2) respectively, for Black patients and 80 (9) and 3.3 (1.2), respectively, for White patients (p<0.0001). The mean (SD) CHAD2S2-VASc scores were 4.5 (1.9) for White patients, and 5.3 (1.9) for Black patients with p<0.0001, respectively. Black patients (vs White patients) had a higher non-treatment (no DOAC or warfarin) rate (56.1% vs 47.4%, p<0.0001) across the US which was particularly notable in the southeast. In addition, treatment rates were highly variable within each US state. Counties with dense population more frequently demonstrated significant differences by race than counties with sparse population.

Conclusion: Our study showed differences in the use of OACs across US counties and among various racial groups. These disparities highlighted the areas of unmet need for both Black and White patients.

MeSH terms

  • Administration, Oral
  • Aged
  • Aged, 80 and over
  • Anticoagulants* / administration & dosage
  • Anticoagulants* / therapeutic use
  • Atrial Fibrillation* / drug therapy
  • Atrial Fibrillation* / ethnology
  • Black or African American / statistics & numerical data
  • Female
  • Humans
  • Male
  • Medicare* / statistics & numerical data
  • Stroke / drug therapy
  • Stroke / epidemiology
  • Stroke / ethnology
  • United States / epidemiology
  • Warfarin / administration & dosage
  • Warfarin / therapeutic use
  • White
  • White People / statistics & numerical data

Substances

  • Anticoagulants
  • Warfarin

Grants and funding

This study was financially supported by the Bristol Myers Squibb-Pfizer Alliance. This study was also financially supported by the Bristol Myers Squibb in the form of salaries for authors AK, NA, MH, and JJ. This study was also financially supported by Inova Health System in the form of salary for BDA. This study was also financially supported by Duke University in the form of salary for LRJ. This study was also financially supported by Pfizer in the form of salary for DMH. The specific roles of these authors are articulated in the ‘author contributions’ section. No additional external funding was received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.