PF693 PRIMARY IMMUNE THROMBOCYTOPENIA (ITP) IN THE ELRDELRY AND YOUNGER ADULTS: REAL‐WORLD COMPARATIVE RETROSPECTIVE STUDY FROM THE ITP REGISTRY OF THE HELLENIC SOCIETY OF HEMATOLOGY

Background: As life expectancy increases, elderly patients (pts) with immune thrombocytopenia (ITP) are increasingly being encountered in everyday practice. However, the features of ITP in older adults have not been fully elucidated thus far. Aims: To describe real world characteristics at diagnosis and evaluate disease outcome in a group of elderly pts (> 65 years) with primary ITP as compared to younger pts (>16 years‐ 65 years), using data from the national database (ITP registry) operated under the auspices of the Hellenic Society of Hematology. Methods: The Greek ITP registry recruits pts (n = 1317, to date) nationally through a network of 21 sites. In the present study we retrospectively analyzed data from pts with primary ITP aged over 16 years, who were diagnosed from 1979 to 2018. Results: The total number of evaluable pts was 843. Pts were divided in 2 groups based on age: Group‐1 consisted of 540 pts aged 16–65 years and Group‐2 of 303 pts aged > 65 years. The mean age at diagnosis was 36 years (16.1–64.7) in Group‐1 and 76 years (65.1–99) in Group‐2. The female to male ratio in Group‐1 was 1.9 and in Group‐2 1.1 (P = 0.0012). The median platelet count at diagnosis was significantly higher in Group‐1 (16x10 9 /L, interquartile range: 8–35.7x10 9 /L) than in Group‐2 (12x10 9 /L, interquartile range: 5–29x10 9 /L; P = 0.0014). As expected, significant fewer pts in Group‐1 had co‐morbidities as compared to Group‐2 (54.3% and 87.1%, respectively; P  < 0.0001). Concurrently used medications, including vitamin K antagonists, platelet antagonists, other anticoagulants or non‐steroidal anti‐inflammatory drugs were more frequently reported in Group‐1 than in Group‐2 pts ( P  < 0.0001). Bleeding manifestations at diagnosis were observed at a similar frequency between the two groups, with the exception of menometrorrhagia which was significantly more frequent in Group‐1 that in Group‐2 pts, as expected ( P  < 0.0001). Bone marrow examination was performed more frequently in Group‐1 pts, whereas antiphospholipid antibody, platelet associated antibody, antinuclear antibody, HIV and hepatitis C testing were more frequently performed in Group‐2 pts. Treatment was given in 88% of Group‐1 and in 91% of Group‐2 patients at diagnosis. Overall response rate did not differ between the two Groups. A similar proportion of Group‐1 and Group‐2 patients were treated with corticosteroids, intravenous IgG or both, rituximab, anti‐D immunoglobulin or thrombopoietin receptor agonists, whereas significant more Group‐1 pts underwent splenectomy ( P  < 0.0001). Follow‐up of at least 1 year from diagnosis revealed that a similar proportion of Group‐1 and Group‐2 patients had developed chronic ITP. During follow‐up, 2 Group‐1 pts and 11 Group‐2 pts died (1.4% and 12%, respectively; P = 0.0003). Three deaths in Group‐2 were considered to be related to ITP. Summary/Conclusion: Elderly pts (Group‐1) presented with lower platelet counts at diagnosis had a higher frequency of comorbidities and used more often anti‐platetet and anticoagulant agents. However, neither the frequency nor the location of bleeding differed between Group‐1 (younger pts) and Group‐2 pts. Age influenced the choice of diagnostic procedures but not that of treatment, with the exception of splenectomy which was performed at significantly lower rate in Goup‐2 pts. Neither the treatment response nor the frequency of chronic ITP differed between Group‐1 and Group‐2 pts. 27% of deaths in Group‐2 pts were ITP‐related, whereas none in Group‐1 pts, thereby underscoring the need for age‐adapted management in elderly pts with ITP.