Racial Disparity in the Prescription of Anticoagulants and Risk of Stroke and Bleeding in Atrial Fibrillation Patients

Abstract

Background: Oral anticoagulant (OAC) therapy is proven to be effective at reducing risk of stroke in patients with atrial fibrillation (AF). However, racial minorities with AF are less likely to be prescribed vitamin K anticoagulants (VKA). There is little information on the racial disparity in the prescription of the non-vitamin K oral anticoagulants (NOACs) and the associated risks of stroke and bleeding.

Methods: We used data from the Northwestern Medicine Enterprise Data Warehouse - a joint initiative across 11 Northwestern Medicine affiliated healthcare centers within metropolitan Chicago, Illinois. Newly diagnosed AF patients between Jan, 2011 and Dec, 2017 with CHA₂DS₂VASc (congestive heart failure, hypertension, age ≥75 years, diabetes, stroke/transient ischemic attack, vascular disease, age 65 to 74 years, female sex) score of 2 or more and no prior history of stroke or major bleeding were eligible. Logistic regression was used to examine differences in the prescription of any OAC and NOACs by race. Racial differences in the associations of NOACs prescription with incident stroke (a composite of ischemic and hemorrhagic stroke and cerebral embolism) and major bleeding were evaluated using Cox regression.

Results: Among 11,575 newly diagnosed AF patients with CHA₂DS₂VASc score of 2 or more, 48.7% (47.8-49.6) were on any OAC and among those 40.1% (38.8.3-41.4) received any NOACs. After adjusting for age, gender, income, insurance status, and stroke risk factors, the odds of receiving any OAC was .69 (95% CI: .58-.83) in blacks, .74 (.53-1.903) in Hispanics, and .75 (.58-.95) in Asians compared to whites. Among anticoagulated patients, blacks and Hispanics had significantly lower odds of receiving NOACs: .72 (.53-.97) and .53 (.29-.99), respectively. Use of NOACs, as compared to VKAs, was associated with significantly lower risk of stroke [.52(.31-.85)] and bleeding [.72(.54-.95)] in whites but not in non-whites [stroke: .71 (.22-2.31); bleeding .83(.43-1.57)] independent of other risk factors.

Conclusions: Racial minorities with AF who are at risk of stroke were less likely to receive any OAC and NOACs specifically compared to whites even after accounting for insurance status, income, and stroke risk factors. Independent of other risk factors, use of NOACs as compared to VKA was associated with significantly lower risk of stroke and bleeding only in whites but not in non-whites.

Keywords: Anticoagulants; atrial fibrillation; bleeding; racial-disparity; stroke.