Comparison between thrombotic risk scores in essential thrombocythemia and survival implications

The conventional thrombotic risk stratification in essential thrombocythemia (ET) distinguishes patients in two risk groups based on previous thrombosis and age (< or >60). The IPSET-thrombosis takes into account four risk factors: age greater than 60 years and the presence of CV risk factors, thrombosis history and JAK2 V617F presence. The revised IPSET-thrombosis uses three adverse variables to delineate four risk categories: age greater than 60, thrombosis history, and JAK2 V617F presence. We compared different risk models in the estimation of thrombotic risk in 191 patients with ET and the role of specific driver mutations affecting overall survival, according to thrombotic risk. We also evaluated the mutational status of patients showing history of thrombosis or cardiovascular events versus patients who did not. Finally, we verified whether the thrombotic risk had a significant impact on survival in our ET patients. The data analysis has been performed through the conventional statistics and overall survival estimated by using the Kaplan-Meyer method. Interestingly, either using the traditional system for thrombotic risk or the IPSET-t prognostic score or the current stratification for the thrombotic risk, high-risk patients are always highly represented. This evidence is of note, being the high-risk category indicated for cytoreduction, affecting quality of life, despite the good overall prognosis of patients with ET diagnosis in general. The analysis of overall survival in our patients, according to different models for thrombotic risk, highlighted the poor prognosis of high-risk patients compared with those with a lower thrombotic risk, in particular when using traditional stratification and current stratification. In conclusion, the occurrence of thrombotic or cardiovascular events represents one of the most severe complications at diagnosis or during follow-up of ET despite current recommendations, having a significant impact on morbidity and survival.