Chronic refractory immune thrombocytopenia in adolescents and young adults.

Summary: Defining immune thrombocytopenia (ITP) in two age groups—children and adults—overlooks the specific clinical features and needs of adolescents and young adults (AYAS). We previously reported a high risk of chronic disease at 12 months (50%); however, data on the course of chronic ITP, the risk of refractoriness and treatment strategies in AYAS are limited. Data from patients aged 12–25 years with chronic primary ITP at 12 months were extracted from three large registries between 2004 and 2021. Clinical and laboratory data were evaluated until 48 months of follow‐up (FU). Refractory ITP was defined as the administration of ≥3 different lines of therapy. A total of 427 AYAS (64% female) with chronic ITP were included. Overall, 7% and 14% were classified as 'refractory' at 12 and 48 months of FU respectively. The proportion of males was greater in the refractory group than in the non‐refractory group (43% vs. 35%). AYAS with refractory disease displayed lower median platelet counts, more bleeding and a higher need for treatment at initial diagnosis and FU than non‐refractory patients. This study reveals that refractory ITP is uncommon in AYAS; however, AYAS with refractory ITP display a high disease burden at all time points, including at initial diagnosis. [ABSTRACT FROM AUTHOR]