Clinical features and outcomes of patients with primary myelofibrosis in Japan: report of a 17-year nationwide survey by the Idiopathic Disorders of Hematopoietic Organs Research Committee of Japan.

We conducted a 17-year nationwide survey (1999-2015) to elucidate the clinical outcomes of patients with primary myelofibrosis (PMF) in Japan. Questionnaires were sent annually to approximately 500 hematology departments. Newly diagnosed patients with PMF were enrolled in this study, and were followed up annually to collect prognostic information.