Bleeding risk in patients with multiple myeloma treated for venous thromboembolism: a MarketScan analysis.

Background: Multiple myeloma (MM) is associated with high risk of venous thromboembolism (VTE). Thromboprophylaxis is thoroughly studied in MM. Contrarily, studies assessing the risk of bleeding in people with MM on anticoagulation are lacking. Objectives: To determine the rate of serious bleeding in patients with MM receiving anticoagulation for VTE and the clinical factors associated with bleeding risk. Methods: Using the MarketScan commercial database, we identified 1298 people with MM treated with anticoagulation for incident VTE events between 2011 and 2019. Hospitalized bleeding was identified using the Cunningham algorithm. Rates of bleeding were calculated and Cox regression identified risk factors for bleeding. Results: Bleeding occurred in 51 (3.9%) cases during median follow-up of 1.13 years. Rate of bleeding among patients with MM on anticoagulation was 24.0 per 1000 person-years. In adjusted regression, factors associated with increased bleeding included age (HR, 1.31 per 10-year increase; 95% CI, 1.03-1.65), Charlson comorbidity index (HR, 1.29 per SD increase; 95% CI, 1.02-1.58), use of antiplatelet agents (HR, 2.4; 95% CI, 1.03-5.68), diabetes (HR, 1.85; 95% CI, 1.06-3.26), and renal disease (HR, 1.80; 95% CI, 1.05-3.16). Cumulative incidence of bleeding was 4.7%, 3.2%, and 3.4% for warfarin, low molecular weight heparin, and direct oral anticoagulants, respectively. Conclusion: In this real-world analysis, the rate of bleeding in people with MM on anticoagulation was comparable to those in other subsets of cancer-related VTE. Bleeding rate was lower with low molecular weight heparin and direct oral anticoagulants than warfarin. Higher comorbidity index, diabetes, antiplatelet agent use, and renal disease were risk factors for serious bleeding.