title: A descriptive analysis of international transfusion practice and bleeding outcomes in patients with acute leukemia.
abstract: BACKGROUND
  Recently, bleeding has been used in platelet (PLT) trials rather than surrogate outcomes. The purpose of this study was to provide a descriptive summary of data from PLT studies conducted in four countries and exploratory analyses to determine the relationship between bleeding and PLT count.
  
  
  METHODS
  A descriptive analysis was performed on original data from the Italian trigger study, the US TRAP study, the Canadian febrile reaction study, and a clinical chart review from one hospital site in the United Kingdom. The relationship between bleeding and PLT count was explored with the Italian data.
  
  
  RESULTS
  A total of 897 patients with acute leukemia received 10,506 PLT transfusions. Grade 3 or Grade 4 WHO bleeding frequency was 28.1 percent (252/897) but varied by country: Italy, 10.8 percent (27/250); United States, 36.4 percent (217/598); Canada, 18.9 percent (7/37); and the United Kingdom, 8.3 percent (1/12). Grade 1 or Grade 2 bleeding was reported only in the Italian study (46.4%[116/250] and 11.6%[29/250], respectively). The relative rates of WHO Grade 2, 3, or 4 bleeding for PLT counts in the ranges of 0 to 4, 5 to 9, 10 to 14, and 15 to 19 (x10(9)/L) were 8.8, 1.9, 1.8, and 1.2, respectively, compared to those counts within the range of 20 to 29 (x10(9)/L).
  
  
  CONCLUSIONS
  The study provides descriptive data on PLT use and frequency of bleeding. When PLT counts were 0x10(9) to 4x10(9) per L there was an eightfold increase in bleeding and a twofold risk increase when counts were 5x10(9) to 14x10(9) per L compared to the 20x10(9) to 29x10(9) per L reference range. The increased rate of bleeding at low counts occurred despite PLT therapy.
authors.affiliation: Department of Medicine, McMaster University, Canadian Blood Services, Hamilton, Ontario, Canada, and the Transfusion and Transplant Immunology Center IRCCS, Maggiore Hospital, Milan, Italy. heddlen@mcmaster.ca
authors.forename: Nancy M
authors.initials: NM
authors.lastname: Heddle
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cook
authors.forename: Chris
authors.initials: C
authors.lastname: Sigouin
authors.forename: Sherrill J
authors.initials: SJ
authors.lastname: Slichter
authors.forename: Mike
authors.initials: M
authors.lastname: Murphy
authors.forename: Paolo
authors.initials: P
authors.lastname: Rebulla
mesh_terms: D000208:Acute Disease; D002170:Canada; D003625:Data Collection; D006470:Hemorrhage / Q000517:prevention & control* / Q000628:therapy; D006801:Humans; D015994:Incidence; D007558:Italy; D007938:Leukemia / Q000150:complications* / Q000628:therapy*; D010976:Platelet Count; D017713:Platelet Transfusion; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D006113:United Kingdom; D014481:United States