Cumulative incidence of remission. Cumulative incidence defined as having a platelet count ≥150 × 10⁹/L on all subsequent follow-up visits without having undergone splenectomy. Data derived from the 343 patients who had platelet counts recorded at all 4 study visits beginning 28 days after diagnosis. Remission was defined as having a platelet count greater than the threshold on all subsequent follow-up visits without having undergone splenectomy.