The safety and efficacy of transfusing red blood cells stored for different durations: a systematic review and meta-analysis of randomized controlled trials.

Objective: The aim of this work was to resolve the uncertainty of whether transfusion of fresher red blood cells (RBCs) is better or not with regard to the safety and efficacy.

Methods: This systematic review was performed in accordance with our protocol registered on PROSPERO (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022379183).

Results: After a literature search, 13,247 records were identified, and 26 randomized controlled trials (RCTs) involving 53,859 participants were eligible and included in this review. The results in our review suggested that there was no significant effect of fresher vs older RBCs on mortality (relative risk [RR] = 1.04; 95% CI, 0.99-1.09; P = .39; I2 = 0%), transfusion reactions (RR = 0.87; 95% CI, 0.57-1.33; P = .64; I2 = 0%). However, the transfusion of fresher RBCs might increase the risk of nosocomial infection (RR = 1.11; 95% CI, 1.02-1.20; P = .02; I2 = 0%), whereas there was no significant difference in the fresh vs old subgroup (RR = 0.87; 95% CI, 0.68 to 1.12; P = .28; I2 = 0%).

Conclusion: Our study updated and reinforced the evidence of previously published systematic reviews that support the safety and efficiency of current practice of issuing the oldest available RBCs in the blood bank inventory.