Cancer-associated thromboembolism: antithrombotic management of hospitalized patients.

Cancer increases risk for venous thromboembolism. Incident thrombocytopenia increases hemorrhagic risk. Hospitalized adults with a cancer diagnosis who received subcutaneous dalteparin in doses adjusted according to platelet count were retrospectively evaluated. Outcomes of interest included nadir platelet counts, transfusions, thromboembolism, and hemorrhage. During a 2-year period of observation, 1854 cancer patients received individualized inpatient treatment with dalteparin. Transfusion was required in 38 of 77 (49.4%) patients with nadir platelet counts < 25 × 10 cells/L as compared with 16 of 75 (21.3%) patients whose nadir platelet counts were 25-50 × 10 cells/L [risk ratio (RR) 2.31; 95% CI 1.42 to 3.78, p < 0.001] and 45 of 1657 (2.7%) patients with platelet counts > 50 × 10 cells/L (RR - 8.07; 95% CI - 4.79 to - 13.59, p < 0.001). Transfusions were administered primarily as supportive therapy. Among transfusion recipients, new or recurrent venous thromboembolism was documented in 2.6%, 0%, and 2.2% of patients with nadir platelet counts of < 25, 25-50, or > 50 × 10 cells/L, respectively (p > 0.9 for all comparisons). Acute blood loss or major bleeding was documented in 10.5%, 12.5%, and 15.6% of patients with platelet counts of < 25, 25-50, or > 50 × 10 cells/L, respectively (p > 0.9 for all comparisons). Among hospitalized cancer patients who received individualized dalteparin treatment, transfusion requirements varied inversely with platelet count. Irrespective of platelet counts, occurrence rates for venous thromboembolism and acute hemorrhage were similar across all treatment groups. Individualized dalteparin treatment provided a consistent pattern of safety and effectiveness.