G20210A mutation in the prothrombin gene and the risk of recurrent venous thromboembolism

OBJECTIVES The study was done to determine whether the G20210A mutation in the prothrombin gene increases the risk of recurrent venous thromboembolism (VTE), both alone and in combination with factor V Leiden. BACKGROUND Several inherited defects of coagulation are associated with inc reased risk of first VTE, including a recently identified G20210A mutation in the prothrombin gene. However, whether the presence of this mutation con fers an increased risk of recurrent venous thromboembolism is controversial . METHODS A total of 218 men with incident venous thromboembolism were genoty ped for the prothrombin mutation and for factor V Leiden and were followed prospectively for recurrent VTE over a follow-up period of 7.3 years. RESULTS A total Of 29 men (13.3%) suffered recurrent VTE. Five of the 14 ca rriers of the prothrombin mutation developed recurrent VTE (35.7%; incidenc e rate = 8.70 per 100 person-years), while 24 of 204 individuals who did no t carry the prothrombin mutation developed recurrent VTE (11.8%; incidence rate = 1.76 per 100 person-years). Thus, presence of the G20210A mutation w as associated with an approximate fivefold increased risk for recurrent VTE (crude relative risk [RR] 4.93; 95% confidence interval [CI] 1.9-12.9; p = 0.001; age-, smoking-, and body mass index-adjusted RR 5.28; 95% CI 2.0-14 .0; p = 0.001). In these data, recurrence rates were similar among those wi th an isolated mutation in the prothrombin gene (18.2%) as compared to thos e with an isolated factor V Leiden mutation (19.2%). However, all three stu dy participants who carried both mutations (100%) suffered a recurrent even t during follow-up. CONCLUSIONS In a prospective evaluation of 218 men, the presence of prothro mbin mutation was associated with a significantly increased risk of recurre nt VTE, particularly among those who co-inherited factor V Leiden. (j Am Co il Cardiol 2001;37:215-8) (C) 2001 by the American College of Cardiology.