[Epidemiology and long-term prognosis of ITP].

Research Committee for ITP was organized in 1972 under the support of the Government and since then efforts have been concentrated to elucidate pathophysiology of the disease and to establish better management of patients with ITP. A nation-wide epidemiological survey was conducted with estimates for prevalence of 7,500-10,500(5.5-11.5/100,000 population), with annual incidence of 1,700-4,100. Repeated survey after 10 years gave similar values for both parameters. Effectiveness of various treatments including standard modality and other special approaches was evaluated by multicenter collaborative studies, and long-term clinical course and outcome were analyzed to better understand the natural history of ITP. Our insufficient understanding regarding true natural history of ITP was discussed as a problem for the future investigation.