Provoked versus unprovoked venous thromboembolism: Findings from GARFIELD-VTE.

Introduction: Venous thromboembolism (VTE) has a long-term risk of recurrence, dependent on the presence or absence of provoking risk factors at the time of the event.

Objective: To compare clinical characteristics, anticoagulant patterns, and 12-month outcomes in patients with transient provoking factors, active cancer, and unprovoked VTE.

Methods: The Global Anticoagulant Registry in the FIELD (GARFIELD)-VTE is a prospective, observational study that enrolled 10 207 patients with objectively diagnosed VTE from 415 sites in 28 countries.

Results: Patients with transient provoking factors were younger (53.0 years) and more frequently women (61.2%) than patients with unprovoked VTE (60.3 years; 43.0% women) or active cancer (63.6 years; 51.7% women). After 6 months, 59.1% of patients with transient provoking factors remained on anticoagulation, compared to 71.3% with unprovoked VTE and 47.3% with active cancer. At 12 months, this decreased to 36.7%, 51.5%, and 25.4%, respectively. The risk of mortality (hazard ratio [HR], 1.21; 95% confidence interval [CI], 0.90-1.62), recurrent VTE (HR, 0.84; 95% CI, 0.62-1.14), and major bleeding (HR, 1.26; 95% CI, 0.86-1.85) was comparable in patients with transient provoking factors and unprovoked VTE. Patients with minor and major transient provoking factors had a similar risk of recurrent VTE (HR, 0.99; 95% CI, 0.59-1.66), but those with major transient risk factors had a lower risk of death (HR, 0.61; 95% CI, 0.38-0.98).

Conclusion: At 1 year, nearly 40% of patients with transient provoking factors and slightly over half of patients with unprovoked VTE were on anticoagulant treatment. Event rates were comparable between the two groups. Risk of death was higher in patients with minor transient factors than in those with major transient factors.