Low Mean Cell Haemoglobin is a Valuable Parameter of Thrombotic Risk Stratification in Patients with Polycythemia Vera

Objectives: Thrombosis is a leading cause of morbidity and mortality in patients with Philadelphia negative chronic myeloproliferative neoplasms (MPNs). There are many thrombosis risk stratifications used in this patient group taking into consideration the age, thrombosis history and cardiovascular factors (hypertension, hypercholesterinaemia, hyper-trigliceridaemia, thrombocytosis, smoking and diabetes mellitus). In this work we evaluated the possible role of iron deficiency in thrombotic events (TE) of the polycythaemia vera (PV) patients. Methods: We considered the low mean cell haemoglobin (MCH <28 pg) value as a parameter to assess the iron deficiency in the multicentre database (15 Hungarian haematology centres) of our HUMYPRON GROUP (Hungarian MPN Working Group). The MCH values, recorded at the time of diagnosis of 296 patients with polycythemia vera, were retrospectively analysed.Results: The low MCH, at the diagnosis, was found to be a risk factor for thrombotic events occurring after diagnosis (OR: 1.966). It was also shown as an additive and independent parameter in the Tefferi high-risk patient groups, and combining it with Tefferi risk stratification an extremely high thrombotic risk group could be determined (Nagelkerke R square: 0.084). We have supposed that low MCH in PV reveals a disease form featured with a high proliferation activity. Our hypothesis was confirmed with a sub-study (n=52) showing that the high JAK2V617F allele burden was significantly correlated with the low MCH (p=0.005) and the high white blood cell count (WBC) (p<0.001).Conclusions: Iron deficiency, existing at the time of diagnosis of PV, was proven to be a risk factor for imminent thrombotic events. The low MCH was found to be a strong additive factor when it was combined with the known thrombotic risk stratification systems. The low MCH showed significant correlation with the high JAK2V617F allele burden.