Influence of platelet and white blood cell counts on major thrombosis - analysis from a patient registry in essential thrombocythemia

Eur J Haematol. 2016 Dec;97(6):511-516. doi: 10.1111/ejh.12759. Epub 2016 May 23.

Abstract

Objectives: Although guidelines recommend normalization of platelet counts as an appropriate endpoint for treatment in high-risk essential thrombocythemia (ET), retrospective studies could not prove a correlation of diagnostic platelet counts with an increased thrombotic rate. There is, however, an increasing evidence that leukocytosis is an important risk factor for arterial thrombosis in myeloproliferative neoplasms.

Methods: This study considers the Austrian cohort of a European registry regarding the platelet-lowering therapeutic anagrelide. Influence of platelet and white blood cell (WBC) counts on thrombotic risk was assessed.

Results: Using the calculated cutoffs of 574.5 G/L for platelets and 8.48 G/L for WBC counts, respectively, the Cox regression analysis revealed a clear influence of elevated platelets (P = 0.008) and WBC counts (P = 0.011) on the occurrence of major thrombotic events. The time to a major thrombotic event was shortest (P < 0.001) and the frequency related to 100 patient-years was highest (P = <0.001) when both platelet and WBC counts ranged above the calculated cutoffs.

Conclusion: Our data add evidence to the impact of platelet and WBC counts on thrombosis in ET. We suspect a particular interaction between platelets and WBC which might be based on a biological interplay depending on particular cell counts.

Keywords: essential thrombocythemia; platelet count; thrombosis risk; white blood cell count.

MeSH terms

  • Aged
  • Blood Platelets*
  • Female
  • Follow-Up Studies
  • Humans
  • Kaplan-Meier Estimate
  • Leukocyte Count*
  • Male
  • Middle Aged
  • Platelet Aggregation Inhibitors / therapeutic use
  • Prognosis
  • Proportional Hazards Models
  • Quinazolines / therapeutic use
  • Registries
  • Risk Assessment
  • Thrombocythemia, Essential / blood*
  • Thrombocythemia, Essential / complications*
  • Thrombocythemia, Essential / diagnosis
  • Thrombocythemia, Essential / epidemiology
  • Thrombosis / blood*
  • Thrombosis / drug therapy
  • Thrombosis / epidemiology
  • Thrombosis / etiology*

Substances

  • Platelet Aggregation Inhibitors
  • Quinazolines
  • anagrelide