Incidence and risk factors of hemorrhagic events in essential thrombocythemia

Patients diagnosed with essential thrombocythemia (ET) experience thrombocytosis and risk reduction is therefore a key goal for therapeutic intervention. Currently, the main risk stratification model as recommended by the European LeukemiaNet is the International Prognostic Score of thrombosis in ET (IPSET-t); however, to date there has been no specific tool developed to aid in the prediction of hemorrhagic risk. Below, we summarize a publication from Tosoni et al. in Annals of Hematology on a retrospective analysis to define both the incidence and risk factors connected to hemorrhagic events in patients with ET.

Study design¹

• Included 308 ET patients diagnosed between 1996–2022
• The primary study endpoint was the incidence of thrombotic and hemorrhagic vascular events linked with possible correlations between associated clinical variables and their occurrence.

Results¹

Thrombotic events

• More patients experienced thrombotic events during the course of ET compared with diagnosis (10.4% vs 6.2%).
• More patients who experienced thrombosis had a high-risk IPSET-t score compared with patients who were high-risk but had no thrombosis at diagnosis (95% vs 47%, p < 0.001).
• No correlation was found between mutational status and thrombotic risk.

Hemorrhagic events

• A total of 40 hemorrhagic events were experienced by 35 patients.
• Risk of hemorrhagic event was increased:
  • in patients at an older age (≥60) at diagnosis by 2.5-fold after diagnosis vs younger patients (p = 0.032); and
  • in patients with a high-risk IPSET-t score by 4.2-fold after diagnosis vs low/intermediate risk (p = 0.003).
• The 10- and 20-year cumulative incidence of hemorrhagic events were 6% and 12%, respectively.
• Hemorrhage-free survival was lower in high-risk IPSET-t patients vs low/intermediate risk (p = 0.002).
• There was no correlation between incidence of hemorrhagic risk, driver mutation, and Janus kinase 2 variant allele frequency.

Key learnings

Highlight the potential use of the IPSET-t model as a global evaluator for vascular events. Limited by its retrospective nature, cohort heterogeneity and small patient number. Future studies should aim to analyze bleeding factors in larger and more homogenous patient cohorts alongside common bleeding classifications to help manage the increased risk of mortality as a result of thrombotic events.