To determine the clinicopathologic and prognostic features of chronic idiopathic thrombocytopenic purpura (ITP) in adult Chinese patients, we conducted a retrospective analysis of 220 patients seen at a single center over a 40-year period. The female-to-male ratio was 4:1, with a mean age of 42.1 +/- 1.3 years, a mean platelet count of 33.7 +/- 2.3x10(9)/l, and a mean follow-up of 116 +/- 7 months. Initial steroid treatment was required in 142 patients, 67 of whom (47.2%) achieved complete remission (CR). At 470 months, 46% patients remained in CR. Splenectomy was performed in 37 patients: in 23 patients due to primary steroid refractoriness and in 7 patients due to disease relapse following initial CR with steroids. In seven patients, data on response to steroids prior to splenectomy were not available. Splenectomy for steroid nonresponders resulted in an inferior CR rate (13 of 23, 56%) as compared with that for relapses after steroid treatment (7 of 7, 100%) (P<0.05). Compared with patients with negative antinuclear antibody (ANA), those who were ANA positive had similar responses to steroids, but significantly shorter remission after splenectomy (P<0.01). In conclusion, Chinese patients with ITP could maintain long-term remission after steroid therapy and splenectomy. In addition, primary steroid refractoriness and positive ANA were bad prognostic factors of the subsequent response to splenectomy.