Increased risk of venous thrombosis in persons with clinically diagnosed superficial vein thrombosis: results from the MEGA study

Kirsten van Langevelde, Willem M. Lijfering, Frits R. Rosendaal and Suzanne C. Cannegieter


Superficial vein thrombosis (SVT) is regarded a self-limiting disorder, although recent studies showed that ultrasonographically diagnosed SVT is a precursor for venous thrombosis. We aimed to determine whether the same holds true for clinically diagnosed SVT, and to what extent it is associated with thrombophilia in a population-based case-control study (MEGA). We found that a history of clinical SVT was associated with a 6.3-fold (95%CI 5.0-8.0) increased risk of deep-vein thrombosis and a 3.9-fold (95%CI 3.0-5.1) increased risk of pulmonary embolism. Blood group non-O and factor V Leiden showed a small increase in SVT risk in controls, with odds ratios of 1.3 (95%CI 0.9-2.0) and 1.5 (95%CI 0.7-3.3), respectively. In conclusion, clinically diagnosed SVT was a risk factor for venous thrombosis. Given that thrombophilia was only weakly associated with SVT, it is likely that other factors (varicosis, obesity, stasis) also play a role in its etiology.

  • Submitted May 23, 2011.
  • Accepted June 30, 2011.