FROM THE NEW ENGLAND JOURNAL OF MEDICINE
In-hospital mortality did not vary for patients who received transfusions of blood that had been stored for 2 weeks and for patients who got blood that had been stored for 4 weeks, based on results from 20,858 hospitalized patients in the randomized, controlled INFORM (Informing Fresh versus Old Red Cell Management) trial conducted at six hospitals in four countries.
While previous trials have concluded that the storage time of blood did not affect patient mortality, those studies largely included high-risk patients and were not statistically powered to detect small mortality differences, Nancy M. Heddle , professor of medicine and director of the McMaster (University) transfusion research program, Hamilton, Ont., and colleagues reported in an article published online in the New England Journal of Medicine (doi: 10.1056/NEJMoa1609014). Standard practice is to transfuse with the oldest available blood, which can be stored up to 42 days.
Their study included general hospitalized patients who required a red cell transfusion. From April 2012 through October 2015, patients were randomly assigned in a 1:2 ratio patients to receive blood that had been stored for the shortest duration (mean duration 13 days, 6,936 patients) or the longest duration (mean duration 23.6 days, 13,922 patients).
Only patients with type A or O blood were included in the study’s primary analysis, because of the difficulty of achieving a difference of at least 10 days in the mean duration of blood storage with other blood types.
There were 634 deaths (9.1% mortality) among patients in the short-term blood storage group and 1,213 deaths (8.7% mortality) in the long-term blood storage group. The difference was not statistically significant. Similar results were seen when the analysis was expanded to include all 24,736 patients with any blood type; the mortality rates were 9.1% and 8.8%, respectively.
An additional analysis found similar results in three prespecified high-risk subgroups – patients undergoing cardiovascular surgery, those admitted to intensive care, and those with cancer.
INFORM, Current Controlled Trials number ISRCTN08118744 , was funded by the Canadian Institutes of Health Research, Canadian Blood Services, and Health Canada. Ms. Heddle had no relevant financial disclosures.
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