Blood Journal
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A randomized controlled trial comparing standard- and low-dose strategies for transfusion of platelets (SToP) to patients with thrombocytopenia

  1. Nancy M. Heddle1,2,
  2. Richard J. Cook3,
  3. Alan Tinmouth2,4,
  4. C. Tom Kouroukis1,
  5. Tor Hervig5,
  6. Ellen Klapper6,
  7. Joseph M. Brandwein7,
  8. Zbigniew M. Szczepiorkowski8,
  9. James P. AuBuchon8,
  10. Rebecca L. Barty1,
  11. Ker-Ai Lee3, and
  12. for the SToP Study investigators of the BEST Collaborative
  1. 1Department of Medicine, McMaster University, Hamilton, ON;
  2. 2Canadian Blood Services, Ottawa, ON;
  3. 3Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, ON;
  4. 4Ottawa Health Research Institute, Ottawa, ON;
  5. 5Haukeland University Hospital, Bergen, Norway;
  6. 6Cedars-Sinai Medical Center, Los Angeles, CA;
  7. 7University Health Network, Toronto, ON; and
  8. 8Dartmouth-Hitchcock Medical Center, Lebanon, NH


A noninferiority study was performed comparing low-dose and standard-dose prophylactic platelet transfusions. A double-blind randomized controlled trial (RCT) was performed in 6 sites in 3 countries. Thrombocytopenic adults requiring prophylactic platelet transfusion were randomly allocated to standard-dose (300-600 × 109 platelets/product) or low-dose (150- < 300 × 109 platelets/product) platelets. The primary outcome (World Health Organization [WHO] bleeding ≥ grade 2) was assessed daily through clinical examination, patient interview, and chart review. A WHO grade was assigned through adjudication. The Data Safety Monitoring Board stopped the study because the difference in the grade 4 bleeding reached the prespecified threshold of 5%. At this time, 129 patients had been randomized and 119 patients were included in the analysis (58 low dose; 61 standard dose). Three patients in the low-dose arm (5.2%) had grade 4 bleeds compared with none in the standard-dose arm. WHO bleeding grade 2 or higher was 49.2% (30/61) in the standard-dose arm and 51.7% (30/58) in the low-dose group (relative risk [RR], 1.052; 95% confidence interval [CI], 0.737-1.502). A higher rate of grade 4 bleeding in patients receiving low-dose prophylactic platelet transfusions resulted in this RCT being stopped. Whether this finding was due to chance or represents a real difference requires further investigation. These clinical studies are registered on as NCT00420914.

  • Submitted September 12, 2008.
  • Accepted December 15, 2008.
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