2.2 Follow-up endpoints and laboratory metrics
The follow-up endpoint was either June 30, 2022, or patient death. This was achieved by reviewing hospital medical records, laboratory data, conducting telephone interviews, and outpatient reviews. Clinical indicators included clinical manifestations, routine blood tests, platelet transfusion refractoriness (PTR), proteinuria, ruptured red blood cells in peripheral blood, LDH, soluble terminal complement complex sC5b-9, and pathological diagnosis. We define a platelet transfusion–refractory patient as an individual who has received two recent (but not necessarily consecutive) platelet transfusions within a 24 hour window, and where corrected count increment (CCI) was lower than 4500/μl.4