Epidemiology and 3‐year outcomes of combined oral contraceptive–associated distal deep vein thrombosis

Background Distal deep vein thrombosis (infrapopliteal DVT without proximal DVT or pulmonary embolism [PE]) generally shares the same triggering risks factors as proximal DVT. In women of childbearing age, a frequent triggering risk factor is the use of combined oral contraceptive (COC) pills. However, data on the epidemiology and long‐term outcomes of COC‐associated distal DVT are lacking. Objectives To assess the epidemiology and long‐term outcomes of COC‐associated distal DVT. Methods Using data from the OPTIMEV (Optimisation de l’Interrogatoire dans l’evaluation du risque thrombo‐Embolique Veineux [Optimization of Interrogation in the Assessment of Thromboembolic Venous Risk]) multicenter cohort study of patients with objectively confirmed venous thromboembolism (VTE) enrolled between 2004 and 2006, we assessed in nonpregnant or postpartum women aged ≤ 50 years without cancer or history of VTE (i) proportion of COC‐associated distal DVTs among women with distal DVTs and among women with COC‐associated VTEs (distal DVT, proximal DVT, or PE) and (ii) 3‐year incidence of death, bleeding, and VTE recurrence. Results COC‐associated distal DVTs (n = 54) represented 43.9% of all distal DVTs and 51.9% of COC‐associated VTEs. All but one woman with a COC‐associated distal DVT received therapeutic anticoagulation for a median of 3 months. At 3‐year follow‐up, all women with COC‐associated distal DVTs were alive, and none had bled during anticoagulant treatment or had experienced a DVT or PE recurrence after stopping anticoagulants. Similar results were found in patients with COC‐associated proximal DVT and PE: The VTE recurrence rate was 1.7% per patient‐year (PY) and 0% PY, respectively, and there were no deaths or major bleeds in either group. Conclusions Distal DVT was the most frequent clinical presentation of COC‐associated VTE and had similarly favorable long‐term outcomes as other COC‐associated VTE.