Background: The ONCO DVT study demonstrated potential benefits of extended edoxaban treatment in patients with isolated distal deep vein thrombosis in terms of thrombotic risk. However, the risk-benefit balance in patients with anemia remains unclear.
Methods and results: This prespecified subgroup analysis included 601 patients, divided into anemia (n=402) and no-anemia (n=199) groups. The primary endpoint was symptomatic recurrent venous thromboembolism (VTE) or VTE-related death. Anemia was defined as hemoglobin <12 g/dL for women and <13 g/dL for men. In the anemia subgroup, the primary endpoint occurred in 3 (1.5%) and 17 (8.4%) patients in the 12- and 3-month edoxaban treatment groups, respectively (odds ratio [OR] 0.17; 95% confidence interval [CI] 0.05-0.58), compared with 0 and 5 (4.9%) patients, respectively, in the no-anemia subgroup (P interaction=0.997). Major bleeding occurred in 26 (13.1%) and 17 (8.4%) patients with anemia in the 12- and 3-month edoxaban treatment groups, respectively (OR 1.64; 95% CI 0.86-3.14), compared with 2 (2.1%) and 5 (4.9%) patients without anemia (OR 0.67; 95% CI 0.26-1.73; P interaction=0.13).
Conclusions: Regardless of the presence of anemia, edoxaban treatment for 12 months was superior to treatment for 3 months in reducing thrombotic events, whereas the risk of major bleeding did not differ significantly between the 2 treatment groups.
Keywords: Anemia; Bleeding; Cancer-associated thrombosis; Edoxaban; Venous thromboembolism.