Prevalence of risk factors for venous thromboembolism in the Italian population: results of a cross-sectional study from the Master Registry.

The prevalence of major risk factors for VTE may differ according to age, gender and clinical presentation. We tested this hypothesis in a large Italian VTE population. MASTER is a multicenter registry aimed to prospectively collect information on a large cohort of patients with acute VTE. The presence of major risk factors was captured by an electronic data network in consecutive patients with objectively confirmed acute VTE. We enrolled 2,119 patients (49.8% men) of whom 424 (20%) <40 years, 529 (25%) between 41 and 60 years, 943 (44.5%) between 61 and 80 years, and 223 (10.5%) >80 years. The prevalence of known risk factors in the four age groups is 63.9, 52.6, 54.6, and 58.3%, respectively (p = 0.002). Immobilization and severe medical disorders are more commonly associated with VTE in patients >80 years, trauma is significantly more common in patients <40 years than in older patient groups. The prevalence of unprovoked events is the highest in patients 41-60 years, and lowest in patients less than 40 years. After logistic regression analysis, patients with pulmonary embolism are more likely to have known risk factors for VTE than patients with deep vein thrombosis at presentation (p = 0.0021), and women are less likely than men to have an unprovoked VTE (p < 0.0001). In conclusion, a substantial proportion of VTE events remain classified as unprovoked. Unprovoked events are more common in middle aged patients, in men, and in patients presenting with deep vein thrombosis.