title: Transfusion of recently donated (fresh) red blood cells (RBCs) does not improve survival in comparison with current practice, while safety of the oldest stored units is yet to be established: a meta-analysis.
abstract: OBJECTIVE
  Preclinical studies generated the hypothesis that older stored red blood cells (RBCs) can increase transfusion risks. To examine the most updated and complete clinical evidence and compare results between two trial designs, we assessed both observational studies and randomized controlled trials (RCTs) studying the effect of RBC storage age on mortality.
  
  
  METHODS
  Five databases were searched through December 2014 for studies comparing mortality using transfused RBCs having longer and shorter storage times.
  
  
  RESULTS
  Analysis of six RCTs found no significant differences in survival comparing current practice (average storage age of 2 to 3 weeks) to transfusion of 1- to 10-day-old RBCs (OR 0·91, 95% CI 0·77-1·07). RBC storage age was lower in RCTs vs. observational studies (P = 0·01). The 31 observational studies found an increased risk of death (OR 1·13, 95% CI 1·03-1·24) (P = 0·01) with increasing age of RBCs, a different mortality effect than RCTs (P = 0·02).
  
  
  CONCLUSIONS
  RCTs established that transfusion of 1- to 10-day-old stored RBCs is not superior to current practice. The apparent discrepancy in mortality between analyses of RCTs and observational studies may in part relate to differences in hypotheses tested and ages of stored RBCs studied. Further trials investigating 1- to 10-day-old stored RBC benefits would seem of lower priority than studies to determine whether 4- to 6-week stored units have safety and efficacy equivalent to the 2- to 3-week-old stored RBCs commonly transfused today.
authors: Critical Care Medicine Department, Clinical Center, NIH, Bethesda, MD, USA.
authors: K E
authors: KE
authors: Remy
authors: Critical Care Medicine Department, Clinical Center, NIH, Bethesda, MD, USA.
authors: J
authors: J
authors: Sun
authors: Critical Care Medicine Department, Clinical Center, NIH, Bethesda, MD, USA.
authors: D
authors: D
authors: Wang
authors: NIH Library, NIH, Bethesda, MD, USA.
authors: J
authors: J
authors: Welsh
authors: Critical Care Medicine Department, Clinical Center, NIH, Bethesda, MD, USA.
authors: S B
authors: SB
authors: Solomon
authors: Department of Transfusion Medicine, Clinical Center, NIH, Bethesda, MD, USA.
authors: H G
authors: HG
authors: Klein
authors: Critical Care Medicine Department, Clinical Center, NIH, Bethesda, MD, USA.
authors: C
authors: C
authors: Natanson
authors: Critical Care Medicine Department, Clinical Center, NIH, Bethesda, MD, USA.
authors: I
authors: I
authors: Cortés-Puch
mesh_terms: D001793:Blood Preservation / Q000379:methods*; D058731:Blood Safety; D002986:Clinical Trials as Topic; D016208:Databases, Factual; D017707:Erythrocyte Transfusion / Q000009:adverse effects; D004912:Erythrocytes / Q000166:cytology*; D006801:Humans; D016017:Odds Ratio; D013997:Time Factors
keywords: blood safety; clinical trial; quality control; red cell components; transfusion medicine (in general); transfusion therapy