Thrombophilia testing results in patients with a first venous thromboembolic event: should the selection criteria for testing be revisited?

BACKGROUND: After the first episode of venous thromboembolism (VTE), the guidelines recommend selective thrombophilia testing and suggest not to test the patients older than 40 years with a provoked event and all patients above 60.

METHODS: We compared thrombophilia workup results in 544 patients, meeting or not meeting the selection criteria. Homozygous factor V Leiden or prothrombin gene mutation, natural anticoagulant deficiencies, antiphospholipid syndrome or combination of ≥2 disorders were considered a strong thrombophilia.

RESULTS: Thrombophilia was detected in 28.5% and strong thrombophilia in 6.6% of patients. In the subgroup aged 40-60 years, in men with unprovoked cases the prevalence of thrombophilia was 35.7% and that of strong thrombophilia 12.5%; in provoked cases it was 19.5% and 4.9%, respectively. In women aged 40-60 with unprovoked events, thrombophilia was found in 18.8%, in cases provoked solely by estrogens or pregnancy in 40.9%, and in those with another trigger in 9.1%. Comparing the patients above and under 60, thrombophilia was detected in 27.6% and 29.2%, respectively (P=0.67) and strong thrombophilia in 9.1% and 4.7%, respectively (P=0.041). Factors significantly associated with positive thrombophilia testing were family history of VTE (including superficial vein thrombosis) - OR 1.80; 95% CI 1.71-2.77 and proximal location of deep vein thrombosis - OR 1.94; 95% CI 1.25-3.02.

CONCLUSIONS: Of VTE patients not meeting selection criteria for testing, the prevalence of thrombophilia and even strong thrombophilia was high in those older than 60 years. Selection criteria for testing should be respected but in some cases an individual approach might be considered.