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Researchers find unexpected association between younger donor age, female sex and transfusion outcomes


A large Canadian study has shown a link between blood donor characteristics and transfusion recipients’ outcomes. This is the first study to suggest that red blood cell transfusions from young donors and from female donors may be associated with poorer survival in recipients.

Red blood cell transfusions are the most common medical procedure provided in hospitals, with more than 100 million units collected worldwide every year for this purpose, according to the World Health Organization.

“These results are intriguing and suggest that if you require a transfusion, your clinical outcome may be affected by the blood donor’s age and sex,” said senior author Dr. Dean Fergusson, a senior scientist and director of the Clinical Epidemiology Program at The Ottawa Hospital as well as a professor at the University of Ottawa. “However, it is important to remember that our study was observational in nature, which means it cannot be considered definitive evidence.”

The study, published in JAMA Internal Medicine, evaluated the impact of blood donor sex and age on recipient outcomes by linking 30,503 transfusion recipients at The Ottawa Hospital between October 2006 and December 2013 with their respective blood donors (80,755 donors in total). The average age of the recipients was 66.2 years and their outcomes were followed for an average of 2.3 years with a maximum follow-up time of 7.2 years.

The researchers found that recipients of female donor red blood cells were associated with an eight percent increased risk of death (from any cause) per unit transfused compared with recipients of male donor red blood cells. For example, for a recipient that received six units of red blood cells, this would translate into an associated risk of death of 36 percent for recipients of all-female donor blood compared to 27 percent for recipients of all-male donor blood one year later.

The researchers also found similar associations with red blood cells from younger donors. Recipients of blood from donors aged 17- 20 were associated with an eight percent increased risk of death per unit transfused compared with recipients of red blood cells from donors aged 40-50. In addition, recipients of red blood cells from donors aged 20-30 were associated with a six percent increased risk of death per transfused product compared with recipients of red blood cells from donors aged 40-50.

“We need further research to confirm these findings and to look at possible biological mechanisms,” said lead author Dr. Michaël Chassé, an assistant professor at Université Laval and a critical care physician at CHU de Québec Université Laval. “One possibility is that components in the blood of younger donors or female donors may affect the immune system of the transfusion recipient.”

“Though our research suggests that we should investigate what’s behind the associations that we found, there is no definitive evidence yet that proves that one type of blood is better or worse for patients,” says Dr. Jason Acker, co-author on the paper and senior development scientist with Canadian Blood Services. “This study opens up new areas of investigation where we can really dig into the biological explanations and understand true cause and effect. In the meantime, patients continue to receive the safest transfusions possible.”

Importantly, all of the patients in this study needed and received potentially life-saving transfusions. All eligible donors are encouraged to continue to donate.

The ability to link donor and product characteristics to patient outcomes is the result of a unique collaboration between a hospital and a blood operator that has the potential to radically change how clinical practice is informed by research and large data analytics.

The researchers established large transfusion patient databases, including data from The Ottawa Hospital Data Warehouse and the Institute for Clinical Evaluative Sciences (ICES).

This study was conducted by researchers at The Ottawa Hospital, the University of Ottawa, Université Laval and Canadian Blood Services’ Centre for Innovation. They were funded by peer-reviewed competitive grants from the Canadian Institutes of Health Research and Canadian Blood Services. Researchers were also supported by The Ottawa Hospital Foundation.

Full reference: Michaël Chassé, Alan Tinmouth, Jason P Acker, Shane W English, Kumanan Wilson, Greg Knoll, Nadine Shehata, Carl van Walraven, Lauralyn McIntyre, Alan Forster, Tim Ramsay, Dean Fergusson. (2016). Association of blood donor age and sex with recipient survival after red blood cell transfusion. JAMA Internal Medicine.

The Institute for Clinical Evaluative Sciences (ICES) is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. For the latest ICES news, follow us on Twitter: @ICESOntario

The Ottawa Hospital: Inspired by research. Driven by compassion
The Ottawa Hospital is one of Canada’s largest learning and research hospitals with over 1,100 beds, approximately 12,000 staff and an annual budget of over $1.2 billion. Our focus on research and learning helps us develop new and innovative ways to treat patients and improve care. As a multi-campus hospital, affiliated with the University of Ottawa, we deliver specialized care to the Eastern Ontario region, but our techniques and research discoveries are adopted around the world. We engage the community at all levels to support our vision for better patient care. See www.ohri.ca for more information about research at The Ottawa Hospital.

Canadian Blood Services
Canadian Blood Services manages the national supply of blood, blood products and stem cells, and related services for all the provinces and territories (excluding Quebec). We operate an integrated, pan-Canadian service delivery model that includes leading an interprovincial system for organ donation and transplantation. Our national scope, infrastructure and governance make us unique in the Canadian healthcare landscape. Canadian Blood Services is regulated as a biologics manufacturer by Health Canada and primarily funded by the provincial and territorial ministries of health. Canadian Blood Services is a not-for-profit charitable organization.

University of Ottawa
The University of Ottawa is home to over 50,000 students, faculty and staff, who live, work and study in both French and English. Our campus is a crossroads of cultures and ideas, where bold minds come together to inspire game-changing ideas. We are one of Canada’s top 10 research universities—our professors and researchers explore new approaches to today’s challenges. One of a handful of Canadian universities ranked among the top 200 in the world, we attract exceptional thinkers and welcome diverse perspectives from across the globe. www.uottawa.ca


Amelia Buchanan
Senior Communications Specialist
Ottawa Hospital Research Institute
[email protected]
Office: 613-798-5555 x 73687
Cell: 613-297-8315

Canadian Blood Services
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