INCREASED RISK OF VENOUS THROMBOSIS IN CARRIERS OF NATURAL ANTICOAGULANT DEFICIENCIES - RESULTS OF THE FAMILY STUDIES OF THE SPANISH MULTICENTER STUDY ON THROMBOPHILIA (EMET STUDY)

Several studies have demonstrated a higher risk of thrombosis in carri ers of anticoagulant deficiencies than in non-deficient individuals fr om families with thrombophilia. The prevalences in Spain were establis hed in a multicenter study (the EMET study) and all the deficient indi viduals were invited to recruit all available family members to be scr eened for the same deficiency in order to establish the risk of thromb osis in deficient individuals. Five-hundred-and-eighty-three individua ls from 114 families with natural anticoagulant deficiencies were anal ysed. Propositi and relatives with a history of thrombosis were asked about the localization and the age at the first episode and whether or not it was spontaneous. Three families with antithrombin deficiency, 35 with protein C, 60 with protein S, four with plasminogen, four with heparin cofactor II, seven with combined deficiencies and one family with dysfibrinogenemia were included in the analysis. The risk of thro mbosis was increased for individuals deficient in antithrombin (adjust ed odds ratio 21.23; 95% confidence interval 5.71-78.94), protein C (a djusted odds ratio 12.62; 95% confidence interval 4.75-33.51), protein S type I (adjusted odds ratio 19.95; 95% confidence interval 7.40-53. 82), protein S type III (adjusted odds ratio 8.11; 95% confidence inte rval 2.66-21.99) or in protein C plus protein S (adjusted odds ratio 8 .99; 95% confidence interval 2.79-28.93), but not for those deficient in plasminogen or heparin cofactor II. The thrombosis-free survival wa s shortened for deficient individuals in antithrombin (median 30 years ), protein C (median 46 years), protein S type-I (median 48 years), pr otein S type III (median 61 years) and combined protein C and S (media n 40 years). In conclusion, individuals carrying anticoagulant deficie ncies have an increased risk of thrombosis, especially those with anti thrombin, protein C or type I protein S deficiencies. (C) 1998 Rapid S cience Ltd.