title: Effect of storage time of platelet products on clinical outcomes after transfusion: a systematic review and meta-analyses.
abstract: BACKGROUND
  Prolonged storage improves availability of platelet products but could also influence safety and efficacy. This systematic review and meta-analyses summarize and quantify the evidence of the effect of storage time of transfused platelets on clinical outcomes.
  
  
  METHODS
  A systematic search in seven databases was performed up to February 2016. All studies reporting storage time of platelet products and clinical outcomes were included. To quantify heterogeneity, I² was calculated, and to assess publication bias, funnel plots were constructed.
  
  
  RESULTS
  Twenty-three studies reported safety outcomes and fifteen efficacy outcomes. The relative risk of a transfusion reaction after old platelets compared to fresh platelets was 1·53 (95% confidence interval (CI): 1·04-2·25) (12 studies). This was 2·05 (CI:1·47-2·85) before and 1·05 (CI: 0·60-1·84) after implementation of universal leucoreduction. The relative risk of bleeding was 1·13 (CI: 0·97-1·32) for old platelets compared to fresh (five studies). The transfusion interval was 0·25 days (CI: 0·13; 0·38) shorter after transfusion of old platelets (four studies). Three studies reported use of platelet products: two for haematological patients and one for trauma patients. Selecting only studies in haematological patients, the difference was 4·51 units (CI: 1·92; 7·11).
  
  
  CONCLUSIONS
  Old platelets increase the risk of transfusion reactions in the setting of non-leucoreduction, shorten platelet transfusion intervals, thereby increase the numbers of platelet transfusions in haematological patients, and may increase the risk of bleeding.
authors.affiliation: Center for Clinical Transfusion Research, Sanquin Research, Leiden, The Netherlands.|Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: A L
authors.identifier: http://orcid.org/0000-0002-1658-9257
authors.initials: AL
authors.lastname: Kreuger
authors.affiliation: Center for Clinical Transfusion Research, Sanquin Research, Leiden, The Netherlands.|Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: C
authors.initials: C
authors.lastname: Caram-Deelder
authors.affiliation: Center for Clinical Transfusion Research, Sanquin Research, Leiden, The Netherlands.|Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Jacobse
authors.affiliation: Center for Clinical Transfusion Research, Sanquin Research, Leiden, The Netherlands.|Department of Hematology, Hagaziekenhuis, Den Haag, The Netherlands.
authors.forename: J-L
authors.initials: JL
authors.lastname: Kerkhoffs
authors.affiliation: Center for Clinical Transfusion Research, Sanquin Research, Leiden, The Netherlands.|Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: J G
authors.initials: JG
authors.lastname: van der Bom
authors.affiliation: Center for Clinical Transfusion Research, Sanquin Research, Leiden, The Netherlands.|Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: R A
authors.identifier: http://orcid.org/0000-0002-6545-7277
authors.initials: RA
authors.lastname: Middelburg
mesh_terms: D006470:Hemorrhage / Q000209:etiology; D006801:Humans; D017713:Platelet Transfusion / Q000009:adverse effects*; D013921:Thrombocytopenia / Q000628:therapy*; D016896:Treatment Outcome
keywords: blood platelets; haemorrhage; meta-analyses; platelet transfusion; transfusion reaction