Critically ill patients who received transfusions of the freshest-available red cells had a mortality rate similar to that of patients who received standard-issue, oldest-available red cells, according to results from a large randomized trial.
In some earlier studies, transfusion of older red cells was linked to increased mortality for critically ill, surgical, and trauma patients. But the new results provide “strong evidence” that transfusing very fresh red cells rather than older red cells “provides no clinically meaningful benefits” in the critically ill population, reported
“Our results support the current international usual practice of transfusing patients with the oldest red cells available,” the researchers wrote in the report on the trial, known as TRANSFUSE (Standard Issue Transfusion versus Fresher Red-Cell Use in Intensive Care).
Red cells are stored up to 42 days and can undergo biochemical, structural, or metabolic changes during that time that “may cause harm,” the researchers wrote. However, blood banks typically issue the oldest compatible red cell units available to them, and it’s uncertain whether doing so increases mortality.
To see if the age of red cells impacted mortality, Dr. Cooper and has colleagues at 59 centers in five countries randomized 4,994 critically ill adults to receive the freshest-available or standard oldest-available red cells (N Engl J Med. 2017;377:1858-67).
At 90 days after transfusion, mortality was 24.8% in the group of patients receiving the freshest-available red cells, and 24.1% for the oldest-available group, or an absolute risk difference of just 0.7 percentage points (95% confidence interval, –1.7 to 3.1; P = .57).
“Among the many secondary outcomes tested, we noted a nominal difference in febrile nonhemolytic transfusion reactions that was small, and we are not sure of its clinical significance,” the researchers wrote.
The average duration of red cell storage was 11.8 days versus 22.4 days for the freshest-available and oldest-available groups, respectively.
The TRANSFUSE trial is not the first to suggest that age of red blood cells does not make a difference in mortality after transfusion. There were two earlier trials, ABLE (Age of Blood Evaluation) and INFORM (Informing Fresh versus Old Red Cell Management) that came to similar conclusions. However, the ABLE trial had a small sample size, and INFORM had “limited outcome data” including a low mortality rate “suggesting low illness severity,” the researchers noted.
“The lower in-hospital mortality in the ICU subgroup in the INFORM trial (13.0%) than that observed in our trial at 90 days (24.5%) is consistent with lower illness severity in the INFORM patients,” they wrote.
The study was funded by organizations including the Australian National Health and Medical Research Council. Dr. Cooper reported receiving consulting fees from Eustralis Pharmaceuticals that were paid to Monash University. No other potential conflicts of interest were reported.