Evaluating bleeding severity in immune thrombocytopenia (ITP)

Despite immune thrombocytopenia (ITP) being one of the most common conditions encountered by the pediatric hematologist, relatively few prospective investigations of ITP exist, and treatment approaches remain highly variable. The ideal prospective clinical trial would use a reduction in severe bleeding as an outcome; however, recent data shows that due to the rarity of severe bleeding events such a trial is not feasible due to the large number of children needed to be enrolled on such studies. Therefore, platelet count is often used a surrogate risk for bleeding severity and an increase in platelet count as the primary outcome in clinical trials. Reliance solely on the platelet count fails to account for relevant patient-related outcomes, among them bleeding severity. Bleeding assessment instruments published to date lack validity and reliability. Therefore, rigorous methods to design and analysis of patient-related outcome measurement tools need to be applied. Once designed appropriately, these measures can be applied to enhance research and help to guide treatment for those patients who truly need it.