Age of Transfused Blood Does Not Affect Mortality

Nicola M. Parry, DVM

September 29, 2017

Transfusing critically ill patients with the freshest available red cells, rather than with standard-issue (oldest available) red cells, provides no clinically meaningful benefits, a new study suggests.

D. James Cooper, MD, Monash University, Melbourne, Victoria, Australia, and colleagues published the results of the TRANSFUSE trial online September 27 in the New England Journal of Medicine.

"The age of transfused red cells did not affect 90-day mortality among critically ill adults," the authors write.

To minimize blood disposal, blood banks typically dispense the oldest units of available blood first. However, as red cells age during storage, they undergo biochemical, metabolic, and structural changes that have been referred to as the "storage lesion." 

According to the authors, transfusion of older red cells has been associated with a range of adverse effects, including increased morbidity and mortality among critically ill patients.

The researchers therefore conducted a multicenter, randomized trial to compare the effect of transfusing the freshest available red cells with that of standard-issue red cells in 4919 high-risk, critically ill patients. The trial took place from November 2012 through December 2016 at 59 centers in five countries.

The researchers randomly assigned 2457 patients to the short-term storage (mean storage duration, 11.8 days) group and 2462 patients to the long-term storage (mean storage duration, 22.4 days) group.

The primary outcome was 90-day all-cause mortality.

At 90 days, 610 patients (24.8%) in the short-term group and 594 (24.1%) in the long-term group had died — an absolute risk difference of 0.7 percentage points (95% confidence interval [CI], –1.7 to 3.1 percentage points), which did not reach statistical significance (P = .57)

And at 180 days, the absolute risk difference was 0.4 percentage points (95% CI, –2.1 to 3 percentage points; P = .75).

For secondary outcomes, more patients in the short-term group experienced febrile nonhemolytic transfusion reactions (5% vs 3.6%; absolute risk difference, 1.4 percentage points; 95% CI, 0.3 - 2.6 percentage points; odds ratio [OR], 1.42; 95% CI, 1.07 - 1.88; P = .01). And the results were similar after adjustment (adjusted OR, 1.45; 95% CI, 1.09 - 1.93; P = .01).

However, the study showed no statistically significant differences between the groups for various other secondary outcomes: 28-day mortality (P = .61), rates of persistent organ dysfunction or death at 28 days (P = .39), new bloodstream infections (P = .65), days alive and free of mechanical ventilation (P = .81) or renal-replacement therapy (P = .97) at 28 days. or intensive care unit duration of stay (P = .86).

"There was no benefit associated with the freshest available red cells with regard to the primary or secondary outcomes," the authors note, concluding that these findings "support the current international usual practice of transfusing patients with the oldest red cells available."

"This multicenter study adds a lot of clarity to a topic that hits home for our transfusion medicine community," Justin D. Kreuter, MD, the medical director of Mayo Clinic's Blood Donor Program in Rochester, Minnesota, told Medscape Medical News.

He emphasized that the current standard practice of issuing blood "first in, first out" ensures that the greatest number of blood donations are transfused. "However, our primary duty is to our patients," he stressed. "This study affirms that our standard practice of issuing oldest blood units, which ensures optimal use of our limited blood inventories, is also best for our patients."

He expressed surprise that younger units of blood were associated with significantly more febrile nonhemolytic transfusion reactions. "Although this type of reaction is not fatal, it can be uncomfortable for patients and certainly increases blood wastage," he noted.

This study was supported by grants from the Australian National Health and Medical Research Council (NHMRC), the Health Research Council of New Zealand, and the Irish Health Research Board and by funding from the Australian Red Cross Blood Service. During the conduct of this study, five authors reported receiving grant support from the Australian NHMRC, three authors reported receiving grant support from the Health Research Council of New Zealand, one author reported receiving grant support from the Australian Red Cross Blood Service, two authors reported receiving grant support from the Irish Health Research Board, and two authors reported receiving grant support from the Australian National Blood Authority. One author reported receiving nonfinancial support for data collection and investigation from the Australian Red Cross Blood Service. One author also reported being a principal investigator on the INFORM CIHR grant, but not a site investigator role for INFORM. Outside the submitted work, one author reported receiving consulting fees for Eustralis Pharmaceutical Ltd, and another author reported serving as a member of the Blood Service Medical Advisory Committee of the Australian Red Cross Blood Service. The remaining authors have disclosed no relevant financial relationships.

N Engl J Med. Published online September 27, 2017. Abstract

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