Symptomatic versus asymptomatic patients in congenital hypoplasminogenemia: a statistical analysis

In the present study, the prevalence of thromboembolic events in patients suffering from type I plasminogen deficiency was evaluated. One hundred and twelve affected subjects belonging to twenty-eight kindreds were gathered from the literature and from personal observations. The incidence of thrombosis found in this group was compared with those seen in: a) 86 unaffected family members; b) 100 hospitalized patients; c) 100 outpatient clinic patients. In the latter two groups, congenital clotting disorders were excluded. Thrombotic manifestations were found in 25.8% of patients with plasminogen deficiency, a figure which was statistically different from those found in unaffected family members (1.16%, p < 0.001), hospitalized patients (3%, p < 0.001) and outpatient clinic patients (5%, p < 0.001). In twenty-four kindreds with hypoplasminogenemia, data concerning the actuarial ages at first thrombotic event were available for construction of thrombosis-free survival curves by the Cutler-Ederer method. The difference between the two curves, corresponding to affected and unaffected family members respectively, were statistically significant (p < 0.01). In conclusion, although the incidence of thromboembolic events in type I plasminogen deficiency is certainly lower than that described in other congenital clotting disorders such as AT III, protein C and protein S, patients with hypoplasminogenemia should be considered at risk for thrombosis, particularly when triggering factors are present.