Effect of storage time of platelet products on clinical outcomes after transfusion: a systematic review and meta‐analyses

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). CONCLUSION: 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.