Patients with myelodysplastic syndromes (MDS) frequently become dependent on blood transfusions. We analyzed the total transfusion support required, and its complications and cost, following the diagnosis of MDS (total period = 79.7 patient-years) in 50 patients followed at the Minneapolis VA Medical Center. From diagnosis of MDS to transformation to AML or death (the MDS phase), 41 patients (82%) required transfusions. The median numbers of transfused blood products per patient per year of follow-up in the MDS phase were: packed red blood cells (pRBC), 11.1 (range, 0-91.3) units, random donor platelets (RDP), 6.8 (range, 0-581) units, and single donor apheresis platelet packs (SDP): 0 (range, 0-40) collections. In the AML phase (time from diagnosis of secondary AML to death or last follow-up), median transfusion requirements per patient (n = 5) were 24 (range, 8-88) units pRBC, 94 (range, 24-480) units RDP and 3 (range, 0-19) collections of SDP. Overall, 80% of patients required either special processing or selection of blood products, had reactions to blood products or required premedications (specified/complicated transfusions); 94% of all pRBC and 97% of all platelet transfusions were specified/complicated. The median cost of transfusions per patient was $4048 (range, $0-73 210) during the MDS phase and $13 210 (range, $5288-59 010) during the AML phase. During the MDS phase, the median cost was $4877 (range, $0-67 050) per patient-year of follow-up; the major proportion of this cost was for pRBC transfusions. Long-term support with frequent transfusions for MDS usually requires specially selected or processed blood products, and is associated with a high incidence of transfusion reactions. This study provides baseline data on the costs of transfusion support for MDS, and can be used for comparing resource utilization and costs of long-term transfusion support (supportive care) with growth factor therapy or disease-modifying modalities such as allogeneic transplantation. (C) 1999 Elsevier Science Ltd. All rights reserved.