Primary immune thrombocytopenia (ITP) is an uncommon disease characterised by a low platelet count, which may cause the patient to have a higher risk or increased duration of bleeding. Individual hospitals only encounter a small number of ITP patients each year which makes it difficult to study this disease. By creating this disease registry, we will be able to build a more complete picture of ITP, including treatment practices, through collecting information about the condition from patients across several hospitals in several countries. Research of this kind will help future patients by providing doctors with information about ITP, and about how patients have been treated.

This is an observational disease registry database for recently-diagnosed adult patients with primary ITP that aims to understand the natural history of this rare disease and disease management. Participating investigators will prospectively enter real-world patient data on their enrolled patients with a minimum of 2 years follow up.

Data from this registry will be used to generate descriptive statistics on demographics, clinical characteristics including prevalence and incidence of co-morbidities, treatment patterns, and adverse outcomes (resulting from treatment or disease) on ITP patients on an annual basis. The information will be generated at the national or combined-country level. Furthermore, each institution will have an access to its data and may choose to generate descriptive statistics for its specific institution on a more frequent, ad-hoc basis. New research questions or questions addressing a subset of registry patients to take advantage of combined registry data will require a separate protocol and review by independent committees

The focus of this protocol is on adults with primary ITP, however, in future there may be interest to expand the population to explore secondary ITP patients as well. Hence, this registry is built to allow for some optional preliminary information related to secondary ITP to be captured.

Multi-site participation of this registry project will be rolled out in stages, and will be offered to centres with appropriate expertise. Pilot countries included Australia, Korea, Taiwan, Singapore, Malaysia, Japan, Thailand and Turkey and sites will be selected based on their potential research (interest, resources, and expected patient volume). Additional sites may be added in the future from countries in Asia Pacific, Middle East and Latin America. Japan has an independent national ITP registry run by the government, however voluntary participation of interested Japanese investigators in this database will be welcomed, therefore allowing comparison of data between Japanese and non-Japanese patients.

Inclusion Criteria:

1. Recently-diagnosed (i.e. < 6 months) primary ITP adults patients (≥ 18 years) characterized by platelet counts less than 100x109/L as defined by the International Working Group1.
2. Able to provide written consent for data to be included in the registry

Adults recently-diagnosed with primary ITP will be prospectively enrolled into the registry. In cases where prospective data collection is not possible from initial diagnosis, eg if sites see mainly referred patients, those patients with pre-existing ITP of no longer than 6 months duration since diagnosis will be allowed into the registry, provided they are still prospectively being followed up or under ongoing review / treatment at the participating institution.