Transfusion threshold and bleeding risk in malignancy-related thrombocytopenia

Background: The association between platelet counts, risk of bleeding, and transfusions in patients with thrombocytopenia related to stem cell transplant (SCT) or chemotherapy is not clear, except at very low platelet counts.

Study design: Secondary analysis of a multicenter, randomized controlled trial, stratified by cause of thrombocytopenia: autologous or syngeneic SCT (AUTO), allogeneic SCT (ALLO), or chemotherapy for hematologic malignancy without SCT (CHEMO).

Setting: Twenty-six hospitals from 2004 to 2007.

Synopsis: The PLADO trial enrolled more than 1,200 patients aged 18 years and older expected to experience a period of hypoproliferative thrombocytopenia as a result of chemotherapy or SCT, and randomized them to low, medium, or high doses of prophylactic platelets. This secondary analysis assessed laboratory predictors of bleeding, and the effect of transfusion.

Of 1,077 patients who received platelet transfusions, there were no differences between dose groups for any bleeding outcomes. Over a wide range of platelet counts, the ALLO stratum had a higher risk of bleeding than other strata, with clinically significant bleeding on 21% of patient-days in the ALLO stratum, compared with 19% in the AUTO stratum and 11% in the CHEMO stratum (P less than .001). Risk for bleeding was significantly higher at platelet counts of equal to or less than 5×109/L compared with platelet counts greater than or equal to 81×109/L. Higher aPTT and INR were also associated with higher risk of clinically significant bleeding. In a multipredictor model, only hematocrit was significantly associated with more severe bleeding. Neither platelet transfusion nor RBC transfusion reduced the risk of bleeding on the following day, although the authors note some possibility of confounding by indication.

Bottom line: Predictors of overall increased risk for bleeding in patients with secondary hypoproliferative thrombocytopenia were treatment stratum, platelet counts less than or equal to 5×109/L, hematocrit less than 25%, INR greater than 1.2, and aPTT greater than 30 seconds. This study challenges the conventional wisdom that transfusions reduce bleeding risk in patients with secondary hypoproliferative thrombocytopenia.

Citation: Uhl L, Assmann SF, Hamza TH, et al. Laboratory predictors of bleeding and the effect of platelet and RBC transfusions on bleeding outcomes in the PLADO trial. Blood. 2017;130(10):1247-58.