Prognostic factors for thrombosis, myelofibrosis, and leukemia in essential thrombocythemia: a study of 605 patients

1 Division of Hematology and 2 Department of Surgical Pathology, Fondazione IRCCS Policlinico San Matteo, University of Pavia, Pavia, Italy Correspondence: Francesco Passamonti, M.D., Division of Hematology, University of Pavia, Fondazione IRCCS Policlinico San Matteo, viale Golgi 19, 27100 Pavia, Italy. E-mail: f.passamonti{at}smatteo.pv.it Background: Essential thrombocythemia is a chronic myeloproliferative disorder; patients with this disorder have a propensity to develop thrombosis, myelofibrosis, and leukemia. Design and Methods: We studied 605 patients with essential thrombocythemia (follow-up 4596 person-years) with the aim of defining prognostic factors for thrombosis, myelofibrosis, and leukemia during follow-up. Results: Sixty-six patients (11%) developed thrombosis with a 10-year risk of 14%. Age >60 years ( p 60 years ( p