Association between thrombophilia and seated immobility venous thromboembolism

Prolonged work and recreation-related seated immobility increases the risk of venous thromboembolism (VTE). Little is known about links of thrombophilia and prolonged immobility. We sought to determine factors associated with the occurrence of seated immobility venous thromboembolism (SIT). Four hundred and ninety-three consecutive outpatients with a history of first-ever VTE, aged up to 65 years were referred for evaluation of suspected thrombophilia. Exclusion criteria were provoked VTE unless family history of VTE was positive, arterial thrombosis, cancer, infection and chronic inflammatory diseases. The prolonged immobility group was defined as being seated at least 8 h daily and at least 3 h daily without getting up, or 10 h daily and 2 h daily without getting up, or 12 h daily and 1 h daily without getting up during 12 weeks prior to VTE onset. SIT was observed in 115 patients (24.5%). Inherited thrombophilia was more common among SIT patients than in the remainder [Odds ratio (OR) 3.98, 95% confidence interval (CI) 2.55-6.25], with a major impact of factor V Leiden mutation (FVL) (OR 4.86, 95% CI 2.95-8.05). In multivariate analysis, FVL (OR 5.43, 95% CI 3.23-9.15), trauma (OR 2.55, 95% CI 1.30-4.99), current smoking (OR 1.68, 95% CI 1.06-2.67) and varices (OR 2.08, 95% CI 1.27-3.40) were independent predictors of SIT. Moreover, FVL (OR 4.05, 95% CI 2.12-7.76), prothrombin G20210A variant (OR 3.84, 95% CI 1.47-10.05) and computer use (OR 2.84, 95% CI 1.43-5.63) were independent predictors of unprovoked VTE in the SIT group. Inherited thrombophilia, current smoking and varices characterize patients with SIT.