The Risk of Recurrent Venous Thromboembolism in Men and Women

TLDR

The association between a patient’s sex and the risk of recurrent venous thromboembolism (VTE) was previously unknown, prompting a 36‑month follow‑up of 826 patients after their first spontaneous VTE and cessation of oral anticoagulants. The study excluded pregnant patients, those with antithrombin, protein C or S deficiencies, lupus anticoagulant, cancer, or long‑term antithrombotic needs, and defined recurrence as objectively documented symptomatic VTE. Men experienced a markedly higher recurrence rate (20 % vs 6 %, RR 3.6) than women, a difference that persisted after adjustment for age, anticoagulation duration, and thrombophilia status, with 5‑year recurrence rates of 30.7 % versus 8.5 %.

Abstract

Whether a patient's sex is associated with the risk of recurrent venous thromboembolism is unknown.We studied 826 patients for an average of 36 months after a first episode of spontaneous venous thromboembolism and the withdrawal of oral anticoagulants. We excluded pregnant patients and patients with a deficiency of antithrombin, protein C, or protein S; the lupus anticoagulant; cancer; or a requirement for potentially long-term antithrombotic treatment. The end point was objective evidence of a recurrence of symptomatic venous thromboembolism.Venous thromboembolism recurred in 74 of the 373 men, as compared with 28 of the 453 women (20 percent vs. 6 percent; relative risk of recurrence, 3.6; 95 percent confidence interval, 2.3 to 5.5; P<0.001). The risk remained unchanged after adjustment for age, the duration of anticoagulation, and the presence or absence of a first symptomatic pulmonary embolism, factor V Leiden, factor II G20210A, or an elevated level of factor VIII or IX. At five years, the likelihood of recurrence was 30.7 percent among men, as compared with 8.5 percent among women (P<0.001). The relative risk of recurrence was similar among women who had had their first thrombosis during oral-contraceptive use or hormone-replacement therapy and women in the same age group in whom the first event was idiopathic.The risk of recurrent venous thromboembolism is higher among men than women.