PB0015 - Potential of Racial Bias in Atrial Fibrillation Patients That are Switched from Warfarin to a Direct Oral Anticoagulant

Background: Prior studies suggest racial discrepancy in the use of direct oral anticoagulants in patients with atrial fibrillation.

Aims: Determine if there are residual differences in the proportion of African American and White patients that are switched from warfarin to a direct oral anticoagulant (DOAC) after controlling for demographic, comorbidities, insurance, and social determinants.

Methods: Patients in the Michigan Anticoagulation Quality Improvement Initiative (MAQI2) ongoing registry from November 2009 to August 2022 with atrial fibrillation that were switched from warfarin to a DOAC were matched 1:1 with propensity score (greedy method). Median geographic household income based on zip code from census data could not be matched because of large differences and logistic regression was utilized on the matched populations.

Results: 670 of 674 African American were well matched to 670 of 4952 White patients (Table 1) except for median household income (Table 2). Prior to matching, 936 of 4952 (18.9%) white and 100 of 674 (14.8%) African American patients were switched (P=0.011). After matching, 120 (17.9%) and 99 (14.8%) of 670 white or African American patients were switched (P=0.21). The odds ratio (OR) for switching was not different between races when controlling for median income (OR = 0.83, 95% CI 0.59 – 1.16).

Conclusion(s): At first glance, African American patients with atrial fibrillation seem to be switched from warfarin to a DOAC less frequently. However, after controlling for differences in the populations, there is no longer any difference by race, arguing against implicit racial bias as a plausible explanation. Median household income is approximately a third lower in African American patients attending our 6 anticoagulation clinics and likely represents the largest barrier to DOAC use. We are actively working on processes with patient assistance programs to decrease co-pays to allow all our patients to receive the best anticoagulant.