The incidence and clinical burden of immune thrombocytopenia in pediatric patients in the United States.

Immune thrombocytopenia (ITP) is the most common bleeding disorder diagnosed in children. Characterized by low platelet counts, it leads to reduced clotting abilities and an increased tendency to bleed. The disorder in children is often self-limiting. However, approximately 25% of children develop persistent or chronic ITP, and bleeding associated with thrombocytopenia can be life-threatening. The current incidence of ITP in the US and the characterization of the illness among children being managed in routine clinical practice are sparsely reported. This retrospective cohort study leveraged a large US-based commercial claims database to estimate the current incidence of pediatric ITP, the uptake of ITP treatments, and the occurrence of clinical outcomes of interest. Overall, the incidence of ITP in patients <18 years was 8.8 (95% confidence interval; 8.5-9.1) per 100,000 person-years from 2011 to 2016. Within two years of ITP onset, >31% of patients received IVIg and/or oral corticosteroids. Other ITP therapies were less common. During this same time period, 50% had at least one bleeding event (ecchymosis, epistaxis, gastrointestinal hemorrhage, etc.), 24% were hospitalized for a bleeding event, and 62% had at least one ITP-related hospitalization. The majority of patients experiencing these events did so within the first month following ITP onset. Our findings confirm the rarity of ITP and relatively low likelihood of chronic disease in young patients, but reveal that for a significant proportion of patients in the newly diagnosed phase, clinical consequences can be serious. Further study of improved treatment methods throughout the disease course is warranted.