title: Development and validation of an International Prognostic Score of thrombosis in World Health Organization-essential thrombocythemia (IPSET-thrombosis).
abstract: Accurate prediction of thrombosis in essential thrombocythemia (ET) provides the platform for prospective studies exploring preventive measures. Current risk stratification for thrombosis in ET is 2-tiered and considers low- and high-risk categories based on the respective absence or presence of either age > 60 years or history of thrombosis. In an international study of 891 patients with World Health Organization (WHO)-defined ET, we identified additional independent risk factors including cardiovascular risk factors and JAK2V617F. Accordingly, we assigned risk scores based on multivariable analysis-derived hazard ratios (HRs) to age > 60 years (HR = 1.5; 1 point), thrombosis history (HR = 1.9; 2 points), cardiovascular risk factors (HR = 1.6; 1 point), and JAK2V617F (HR = 2.0; 2 points) and subsequently devised a 3-tiered prognostic model (low-risk = < 2 points; intermediate-risk = 2 points; and high-risk = > 2 points) using a training set of 535 patients and validated the results in the remaining cohort (n = 356; internal validation set) and in an external validation set (n = 329). Considering all 3 cohorts (n = 1220), the 3-tiered new prognostic model (low-risk n = 474 vs intermediate-risk n = 471 vs high-risk n = 275), with a respective thrombosis risk of 1.03% of patients/y versus 2.35% of patients/y versus 3.56% of patients/y, outperformed the 2-tiered (low-risk 0.95% of patients/y vs high-risk 2.86% of patients/y) conventional risk stratification in predicting future vascular events.
authors.affiliation: Ospedali Riuniti di Bergamo, Bergamo, Italy. tbarbui@ospedaliriuniti.bergamo.it
authors.forename: Tiziano
authors.initials: T
authors.lastname: Barbui
authors.forename: Guido
authors.initials: G
authors.lastname: Finazzi
authors.forename: Alessandra
authors.initials: A
authors.lastname: Carobbio
authors.forename: Juergen
authors.initials: J
authors.lastname: Thiele
authors.forename: Francesco
authors.initials: F
authors.lastname: Passamonti
authors.forename: Elisa
authors.initials: E
authors.lastname: Rumi
authors.forename: Marco
authors.initials: M
authors.lastname: Ruggeri
authors.forename: Francesco
authors.initials: F
authors.lastname: Rodeghiero
authors.forename: Maria Luigia
authors.initials: ML
authors.lastname: Randi
authors.forename: Irene
authors.initials: I
authors.lastname: Bertozzi
authors.forename: Heinz
authors.initials: H
authors.lastname: Gisslinger
authors.forename: Veronika
authors.initials: V
authors.lastname: Buxhofer-Ausch
authors.forename: Valerio
authors.initials: V
authors.lastname: De Stefano
authors.forename: Silvia
authors.initials: S
authors.lastname: Betti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Rambaldi
authors.forename: Alessandro M
authors.initials: AM
authors.lastname: Vannucchi
authors.forename: Ayalew
authors.initials: A
authors.lastname: Tefferi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006801:Humans; D038801:International Classification of Diseases; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012107:Research Design; D012720:Severity of Illness Index; D013920:Thrombocythemia, Essential / Q000145:classification* / Q000175:diagnosis* / Q000473:pathology; D014944:World Health Organization; D055815:Young Adult