Apparent different thrombotic tendency in patients with factor V Leiden and protein C deficiency due to selection of patients

• Published in: Blood 1996-12, Vol.88 (11), p.4205-4208
• Main Authors: LENSEN, R. P. M, ROSENDAAL, F. R, KOSTER, T, ALLAART, C. F, DE RONDE, H, VANDENBROUCKE, J. P, REITSMA, P. H, BERTINA, R. M
• Format: Article
• Language: English
• Subjects: Adult; Age Factors; Age of Onset; Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Case-Control Studies; Disease Susceptibility; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Factor V - genetics; Factor V Deficiency - complications; Factor V Deficiency - epidemiology; Factor V Deficiency - genetics; Female; Humans; Male; Medical sciences; Middle Aged; Protein C - genetics; Protein C Deficiency; Risk; Selection Bias; Thrombosis - epidemiology; Thrombosis - etiology
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.v88.11.4205.4205

Both activated protein C (APC) resistance and protein C deficiency are associated with an increased risk for venous thrombosis. To assess their tendencies to venous thrombosis, we compared the median age of first venous thromboembolism in patients with factor V Leiden or protein C deficiency, who were identified either within unselected consecutive cases with a first deep venous thrombosis derived from a population-based case-control study, or identified by selection of patients with a deep venous thrombosis, who were referred for thrombophilIa work-up. The median age of onset for 92 unselected APC resistant cases was 43 years and for 13 unselected protein C-deficient cases 47 years. The median age at the first thrombotic event for 28 APC-resistant members of thrombophilia families was 29 years and for 50 protein C-deficient members of thrombophilia families 31.5 years. The median age of onset for all unselected patients (n = 105) was 45 years of age (range, 16 to 69 years) and the median age of onset for all selected patients from the thrombophilia families (n = 78) was 30.5 years (range, 16 to 67 years). These results show that within the case-control study and the family studies, the median age of onset is very similar in patients with APC resistance and patients with protein C deficiency. This suggests that APC resistance is not less severe with respect to risk of thrombosis than (heterozygous) protein C deficiency. In conclusion, the median age at which the first thrombosis occurs mainly depends on the way the patients are identified and not on the type of thrombophilia.