Racial Disparities in the Incidence and Risk Factors for Major Bleeding during Extended Anticoagulant Therapy for Venous Thromboembolism

Abstract

Background: Guidelines recommend extended anticoagulation after a first unprovoked venous thromboembolism (VTE) among individuals at low risk of bleeding. However, racial disparities in bleeding risks during extended treatment remain understudied.

Objectives: To compare risks of anticoagulant-associated bleeding and performance of a risk assessment model (RAM) by racial groups during extended VTE treatment.

Methods: We analyzed two prospective cohorts (223 Black participants and 4,314 White participants) with a first unprovoked/weakly provoked VTE who continued anticoagulation after ≥3 months of initial treatment. Primary outcome was adjudicated International Society of Thrombosis and Haemostasis-defined major bleeding. Secondary outcomes included intracranial hemorrhage (ICH), fatal bleeding, and clinically relevant non-major bleeding (CRNMB). We determined incidence and hazard ratios (HRs) by race, then adjusted for bleeding risk factors that included the CHAP (Creatinine, Hemoglobin, Age, antiPlatelet) model.

Results: Black participants had higher prevalence of bleeding risk factors and a 1.9-fold higher risk of major bleeding (HR 1.87, 95% CI 1.04-3.36) compared to White participants. Adjustment attenuated racial difference for major bleeding but not ICH (adjusted HR 2.35, 95% CI 1.23-4.48). Among those classified as low-risk by CHAP, Black participants had numerically higher major bleeding incidence than White participants (2.5 vs. 1.1 per 100 person-years). We did not observe racial disparities in fatal bleeding or CRNMBs.

Conclusion: Black individuals on extended anticoagulation have higher risk of major bleeding compared to White individuals. This effect appears to persist among those classified as low-risk for bleeding. RAMs for anticoagulant-associated bleeding that are generalizable to racialized populations are needed.

Keywords: Ethnic and Racial Minorities; Hemorrhage; Venous thromboembolism.