Characteristics, risk factors and management of venous thromboembolism in immune thrombocytopenia: a retrospective multicentre study

Background An increased risk of thrombosis has been reported in immune thrombocytopenic purpura (ITP), but the characteristics, risk factors of occurrence, recurrence and management of venous thromboembolic events (VTE) have been poorly investigated. Aims To describe VTE and ITP characteristics, distribution of VTE risk factors and their impact on VTE features and recurrence. Methods A retrospective study of patients with ITP and VTE registered in databases of three reference French centres of ITP. Results Among 49 patients, 66 VTE were recorded. The platelet count at the time of the first VTE was <100 x 10(9)/L for 28/43 (65%) patients. In total, 19/48 (40%) patients had at least one positive antiphospholipid test result. For the 10 VTE occurring in eight patients with platelet count <50 x 10(9)/L, ITP treatment was efficient in 7. One haemorrhagic complication associated with anticoagulant (AC) therapy was recorded. For 31/49 (63%) patients, long-term AC therapy could have been discussed after the first VTE, but only 13 received it. A second VTE occurred in 13 (27%) patients. The risk of recurrence was increased in patients with unprovoked VTE before ITP diagnosis or active cancer. Conclusion VTE in ITP mainly occurred in the presence of multiple risk factors of TE. A low platelet count does not protect against VTE. Management with AC therapy despite persistently low platelet count seems possible. Risk of VTE recurrence is high, particularly with a history of unprovoked VTE or active cancer. In this setting, indefinite AC therapy could be discussed.