Thrombocytopenia is defined as a platelet count below 150 × 109 L−1 confirmed by bloodsmear or the presence of clinical signs and symptoms of spontaneous bleeding. Presentations of spontaneous (i.e., non-traumatic) bleeding include purpura (i.e., petechiae, purpura sensu stricto, ecchymosis), hemorrhagic oozing of skin lesions including rashes, hematoma, bruising, hematemesis, hematochezia, occult bleeding per rectum, epistaxis, hemoptysis, hematuria, vaginal bleeding other than menstruation, conjunctival bleeding, intracranial bleeding. Includes Idiopathic thrombocytopenic purpura, idiopathic thrombopenia, ITP
For the background rates we will include the wide definition but differentiate between hospitalization for thrombocytopena (primary diagnosis only) and outpatient diagnosis.