ABSTRACT
BACKGROUND: Data on long-term venous thromboembolism (VTE) recurrence risk according to gender are conflicting. OBJECTIVE: To evaluate long-term VTE recurrence risk after a first VTE in men and women under 50 years old. METHODS: Since May 2000, 875 consecutive patients (315 men, 560 women) with a first symptomatic VTE under 50 years old were enrolled in a French prospective multicentre cohort study and were followed up as long as possible. The primary outcome was symptomatic recurrent VTE during follow-up. RESULTS: At baseline, men were older and had more comorbidities than women. First VTE was mainly unprovoked in men (80.6%) and hormone-related in women (84.3%). During a median follow-up of 7.0 years (inter-quartile range, 5.0-11.0), recurrent VTE occurred in 97 men (30.8%) and in 72 women (12.9%) (annual incidence rates of recurrent VTE of 4.8% versus 1.8%-person-years, P<0.001). However, there was no difference according to gender in subgroups of patients with a first unprovoked VTE (5.8% versus 3.8%-person-years, P = 0.09). In women, duration of hormonal treatment before first VTE did not influence recurrence risk. In multivariable analysis, unprovoked VTE and family history of VTE were independently associated with recurrence (hazard ratio of 2.50 (95% confidence interval, 1.61 to 3.85) and 1.52 (1.11 to 2.09) respectively). LIMITATIONS: Number of women with unprovoked VTE was low. CONCLUSIONS: In patients with a first VTE under 50 years old, a first unprovoked episode and a family history of VTE, but not gender, were associated with a high risk of long-term recurrence.