Association between remote major venous thromboembolism risk factors and the risk of recurrence after a first unprovoked episode.

Background It has been shown that the risk of recurrence of venous thromboembolism (VTE) is significantly lower when provoked by a major risk factor such as surgery or trauma compared with an event that was unprovoked. Objectives In this study we aimed to assess the association between remote exposure (3-12 months prior to VTE) to major VTE risk factors and the risk of recurrent VTE. Methods This was a post-hoc analysis of the REVERSE study, a prospective cohort of 646 patients with a first VTE, not provoked by a recent (< 3 months) major risk factor. Results We found no difference in the recurrence rate in patients with or without remote exposure to major VTE risk factors, including immobilization (hazard-ratio [HR], 1.4; 95% confidence interval, 0.7-2.6), surgery (HR, 0.8; 0.3-1.9) and trauma (HR, 1.3; 0.5-3.6). Conclusion None of the tested risk factors were associated with a lower risk of recurrence during follow-up. Patients with remote exposure to major risk factors at the time of a first VTE should not be managed differently from patients with no VTE risk factors.