Red blood cell distribution width is a useful biomarker to predict bleeding and thrombosis risks in patients with immune thrombocytopenic purpura.

Bleeding and thrombosis are common complications during immune thrombocytopenic purpura (ITP) treatment. There is a strong need to predict bleeding and thrombosis risks before ITP treatment to optimize therapy and appropriately manage these complications. We performed a retrospective cohort study of 120 patients with primary ITP to identify a biomarker to predict bleeding and thrombosis. We compared blood test results at diagnosis between patients with and without bleeding or thrombosis episodes. The standard deviation of red blood cell distribution width (RDW-SD) differed significantly between those with and without bleeding and between those with and without thrombosis, leading us to identify it as a variable representative of risk. RDW-SD was significantly associated with patient age and with histories of several vascular diseases. Multivariate regression analyses showed that RDW integrated several variables associated with vascular risks. RDW-SD was significantly associated with difficulty with corticosteroid discontinuation (hazard ratio [HR], 2.22,  = 0.01), incidence of bleeding (HR, 2.75, < 0.01), incidence of thrombosis (HR, 2.67, < 0.01) and incidence of infection (HR, 1.78,  = 0.04). The RDW-SD value at the time of ITP diagnosis is a useful biomarker to predict the risks of bleeding, thrombosis, and other complications.