Associations between red blood cell and platelet transfusions and the development of idiopathic pneumonia syndrome

Abstract

<bold>Objective:</bold> Blood transfusions are common during hematopoietic stem cell transplant (HSCT) and may contribute to lung injury. We examined the associations between receipt of red blood cell (RBC) and platelet (PLT) transfusions and the occurrence of Idiopathic Pneumonia Syndrome (IPS). <bold>Design:</bold> Retrospective case-control study. <bold>Setting:</bold> Fred Hutchinson Cancer Research Center, 1997 - 2001. Patients: 914 individuals hospitalized for allogeneic HSCT after myeloablative conditioning and transfused allogeneic blood components at their physicians' discretion. <bold>Measurements:</bold> Each IPS case was matched to 2 controls on days-from-transplant. We estimated associations between RBC and PLT transfusions and IPS by post-transplant day 120 using conditional logistic regression models adjusted for IPS risk factors (age, disease indicating transplant, and dose of TBI) and a composite sum of "other" blood components transfused. Timing of transfusions relative to myeloid engraftment and PLT ABO-blood group (match vs. mismatch) were included as potential interaction terms. <bold>Main Results:</bold> The 77 IPS cases (8.4%) received a median of 2 RBC and 4 PLT units in the week prior to IPS onset, compared to 0 and 1 unit, respectively, among controls. In adjusted analyses, each additional PLT unit transfused in the prior week was associated with 33% higher IPS risk (odds ratio 1.33, 95% confidence interval 1.14 - 1.55, p<0.001). Recent transfusions of RBCs and PLTs were each statistically associated with greater risk of IPS when examined without the other; only PLTs retained this significance when both exposures were included in the model. The RBC and PLT associations were similar for subjects developing IPS before or after engraftment and the PLT association was unaffected by ABO-mismatch. <bold>Conclusions:</bold> PLT transfusions, and possibly RBC transfusions, are associated with an increased risk of IPS in the first 120 days after myeloablative HSCT.