Increased mean platelet volume (MPV) is an independent predictor of inferior survival in patients with primary and secondary myelofibrosis.

Neoplastic megakaryopoiesis is a dominant feature of Philadelphia-chromosome-negative myeloproliferative neoplasms (Ph- MPNs), and elevated mean-platelet-volume (MPV) is a common finding in these diseases. The clinical and prognostic significances of MPV in patients with primary (PMF) and secondary myelofibrosis (SMF) have not been reported. We retrospectively analyzed 87 patients with myelofibrosis (66 with PMF, 21 with SMF) treated at our institution. MPV was recorded in addition to other hematological and clinical parameters. MPV was elevated in both PMF and SMF patients in comparison to controls, whereas there was no statistically significant difference between PMF and SMF. Elevated MPV was associated with lower platelets (P = 0.016), higher white blood cells (P = 0.015), higher percentage of circulatory blasts (P = 0.009), higher lactate dehydrogenase (P = 0.011), larger spleen size (P = 0.014) and higher Dynamic International Prognostic score category (P = 0.027), while there was no statistically significant association with driver mutations or degree of bone marrow fibrosis. Higher MPV was univariately associated with inferior overall survival in the whole cohort (HR = 3.82, P = 0.006), PMF (HR = 4.35, P = 0.007) and SMF patients (HR = 7.22, P = 0.034). These associations remained significant in multivariate analyses adjusted for DIPSS. Higher MPV is associated with more aggressive disease features and exhibits powerful independent prognostic properties in both PMF and SMF settings.