Objectives: In patients with essential thrombocythemia (ET), vascular complications contribute to both morbidity and mortality. To better predict the occurrence of thrombotic events, an International Prognostic Score of thrombosis for ET (IPSET-thrombosis) was recently developed. We hereby presented an external validation and analysis of this model in a large Cohort of Chinese Patients.
Methods: We retrospectively evaluated the characteristics and risk factors for thrombosis in 970 Chinese patients with ET and estimated the clinical implications of the IPSET-thrombosis model.
Results: The median follow-up was 49 months (range, 0-360). Chinese ET patients had similar clinical characteristics as Caucasian patients. Similar to the IPSET-thrombosis study, our multivariate analysis revealed age >60 (HR = 1.949), previous thrombosis (HR = 2.484), JAK2V617F mutation (HR = 1.719), and cardiovascular risk factors (HR = 1.877) as independent risk factors for thrombosis. We confirmed that the above risk factors in IPSET-thrombosis, when compared with traditional risk factors (e.g., age ≥60 and previous thrombotic events), were more predictive of thrombotic events (C-index 0.714 vs. 0.647). Classification by IPSET-thrombosis risk groups revealed different cumulative thrombosis-free survival (P < 0.001). For treatment, patients in the intermediate- and high-risk group derived clinical benefit from cytoreductive agents (P < 0.05), but those in the low-risk group did not (P = 0.446). The lower risk of thrombosis on cytoreductive therapy was related to decrease in leukocyte count during the disease course.
Conclusions: We validate the reproducibility of IPSET-thrombosis in Chinese ET patients and provide key clinical implications.
Keywords: primary thrombocythemia; risk factors; thrombosis; treatment.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.