Platelet counts and haemorrhagic diathesis in patients with myelodysplastic syndromes

Objectives: Most patients with myelodysplastic syndromes (MDS) present with single or multiple lineage cytopenias in peripheral blood despite a hypercellular bone marrow. Thrombocytopenia, attributable to ineffective platelet production by dysfunctional megakaryocytes, has been estimated to occur in 40-65% of patients. However, there are hardly any studies on the clinical relevance of low platelet counts in MDS. Methods: We retrospectively analysed data from 2900 patients in the Duesseldorf MDS Registry who were diagnosed at our laboratory between 1982 and 2007. Results: At the time of diagnosis, 43% of the patients had a platelet count lower than 100 000/mu L. Platelets were lower than 20 000/mu L in 7% of the patients, especially in those with advanced stages of MDS, who showed a higher frequency of thrombocytopenia and platelet transfusion dependency. On multivariate analysis, platelet anisometry, hypocellularity of megakaryopoiesis, maturational defects of megakaryocytes and platelets < 20 000/mu L were independent variables showing a statistically significant correlation (P < 0.05) with clinical signs of bleeding. Platelets lower than 100 000/mu L were associated with significantly shortened survival (P < 0.00005), because of an increased risk of progression to acute myeloid leukaemia (AML) (30% vs. 21%) (P < 0.02) and bleeding (16% vs. 8%) (P = 0.0005). Conclusions: Thrombocytopenia is a strong predictor of short survival, with or without haemorrhagic complications.