Venous thrombosis in older people: Prevalence of the factor V gene mutation Q506

OBJECTIVES: Old age is usually considered to be a risk factor for venous th romboembolism, in conjunction with other factors such as heart failure, maj or surgery, cancer, long-term immobilization, and antiphospholipid antibodi es. Generic risk factors, especially inherited deficiencies in coagulation inhibitors, also play a role in the pathogenesis of thrombosis, but these a re usually diagnosed in thrombophilic patients before the age of 50. The fa ctor V Q506 mutation, responsible for activated protein C resistance, was r ecently linked to thromboembolic disease. We therefore investigated the pre valence of biological risk factors in older hospital patients with venous t hromboembolism. DESIGN: A 2-year study period. SETTING: Ivry sur Seine (Paris), France. PARTICIPANTS: Seventy-nine geriatric patients (60 women and 19 men, mean ag e 83 +/- 6.8 years, range 70-102 years) who had had at least one proven epi sode of venous thromboembolism were enrolled over a 2-year period. MEASUREMENTS: Lupus anticoagulant and antithrombin (AT), protein C (PC), an d protein S (PS) levels were determined in plasma. The factor V Q506 mutati on was detected on genomic DNA. RESULTS: Lupus anticoagulant was detected in two women, one of whom also ha d a high level of anticardiolipin IgG, leading to the diagnosis of an antip hospholipid syndrome. No hereditary deficiency in AT, PC, or PS was found, but one patient had an acquired AT deficiency. Interestingly, nine of the 7 9 patients (11.4%, six women and three men) were heterozygous for the facto r V Q506 mutation, although none were homozygous. The only major risk facto r for thrombosis identified in these patients was prolonged immobilization in four cases. Four of the nine patients who were heterozygous for the fact or V Q506 mutation had recurrent thromboembolism, and two of these patients had been immobilized for long periods. CONCLUSIONS: This study confirms that hereditary deficiencies in coagulatio n inhibitors, and the lupus anticoagulant, are rarely involved in the patho genesis of venous thromboembolism in older subjects. In contrast, the facto r V Q506 mutation was frequently associated with thrombosis (11.4% of our p atients) and should, therefore, be considered an important risk factor in t he older people.