No Association Between Length of Red Blood Cell Storage and Mortality Interview with:
Märit Halmin, MD, PhD student

Department of Medical Epidemiology and Biostatistics, Karolinska Institutet,  Stockholm, Sweden What is the background for this study?

Response: During recent years the possible negative effects among recipients of stored red blood cells have been investigated.  Despite a large number of studies, including four randomized trials, no consensus exists.

We therefore performed the hitherto largest register based cohort study of transfused patients, assessing the association between length of storage of red blood cells and mortality. Our design allowed for detection of small but still clinically significant effect, if such exists. What are the main findings?

Response: We found no association between length of red blood cell storage and mortality. The mortality difference comparing patients receiving blood units stored 30-42 days with patients receiving blood units stored 10-19 days was as small as-0.2% (95% confidence interval, -0.5-0.1%). Even among patients who received more than 6 RBC units stored 30 days or more, the hazard ratio of death was 1.00 (95% confidence interval; 0.96-1.05), as compared to patients not receiving any such units. What should readers take away from your report?

Response: A reduction in storage time might threaten the availability of blood products. Our findings suggest that current practice of storing red blood cells for up to 42 days is safe and we see no reason to change this practice. What recommendations do you have for future research as a result of this study?

Response: We used three different analytical approaches in assessing the association of storage time of red blood cells and mortality, and our null result was consistent throughout all analyses. This strengthens our conclusion and minimize the risk of residual confounding. Thank you for your contribution to the community.


Halmin M, Rostgaard K, Lee BK, Wikman A, Norda R, Nielsen KR, et al. Length of Storage of Red Blood Cells and Patient Survival After Blood Transfusion: A Binational Cohort Study. Ann Intern Med. [Epub ahead of print 20 December 2016] doi: 10.7326/M16-1415

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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