P1625: clinical and laboratory characteristics of adult patients with primary immune thrombocytopenia in eastern austria

Topic: 33. Bleeding disorders (congenital and acquired) Background: Primary immune thrombocytopenia (ITP) is a rare acquired autoimmune disease, characterized through isolated thrombocytopenia (<100 x109/L) associated with an increased bleeding risk but also a paradoxically increased risk for thromboembolic events. Aims: Detailed clinical data on adult patients with primary ITP are scarce, due to the rarity of primary ITP. The Vienna ITP biobank on adult patients with primary ITP aims to capture longitudinal clinical data to further characterize ITP patients in Eastern Austria. Methods: The Vienna ITP biobank is an ongoing biobank study conducted at two hematological centers in Eastern Austria (Medical University of Vienna and Hanusch Hospital Vienna) and prospectively collects data of patients diagnosed with primary ITP (EC 1843/2016). Patient recruitment started in 2016 and is ongoing. Patients with primary ITP older than 18 years and with a platelet count of ≤150 x109/L in case of no ITP-specific treatment are included in the ITP Biobank. Active neoplastic disease, secondary/hereditary thrombocytopenia, secondary ITP or a platelet count >150 G/L without treatment are exclusion criteria. Blood for laboratory analyses is sampled and the individual medical and bleeding history of each patient is recorded at each visit. Bleeding severity is assessed using the ITP ISTH bleeding assessment tool (SMOG BS) and Vicenza BS. Results: Of 168 included patients, 2 withdrew consent, 5 turned out as EDTA-dependent pseudothrombocytopenia directly after patient inclusion and in 4 patients were uncovered as secondary ITP. Thus, the study cohort comprises a total number of 157 patients. Patients’ and ITP related characteristics are shown in Tables 1 In total, 39 patients (24.8%) had acute, 13 (8.3%) persistent and 105 (66.8%) chronic ITP at study inclusion. The majority of patients were female, and the mean age was 45.0 years. Almost half of the patients were under ITP treatment at the time of recruitment and 15 (9.5%) were splenectomized. The median (range) bleeding score was 1.0 (0.0-4.0), 32 patients (20.4%) had no bleeding at study inclusion. Anti-platelet antibodies were detected in 52 out of 125 patients with available measurements (41.6%), most of them directed against GP IIb/IIIa. Summary/Conclusion: Our cohort of ITP patients shows typical characteristics in respect to clinical and laboratory factors such as age distribution, female predominance, or antibody positivity. The in-depth clinical characterization of primary ITP patients of Eastern Austria in the Vienna ITP biobank will facilitate research projects in the future. Sponsor: The biobank from which this data derives is supported by Novartis, Swedish Orphan Biovitrum (SOBI), MedMedia Verlag und Mediaservice GmbH and AMGEN GmbHKeywords: Clinical data, Chronic ITP, Anti-platelet antibody, ITP