Blood from donors of the same sex increases survival rates

Survival rates increase if patients undergoing a blood transfusion receive blood from a donor of the same sex, according to sensational new research from Rigshospitalet.


Photo: According to Professor Pär I. Johansson, the sex of a blood donor is a piece in the complex jigsaw puzzle of factors that affect survival rates after blood treatment.

Survival rates could increase if hospitals were better at matching the sex of donors and patients who need blood transfusions according to new research by Professor Pär I. Johansson and PhD student Peter Bruun-Rasmussen from the Blood Bank at Rigshospitalet. 

The results of the study have been published in the prestigious journal Lancet e-Clinical Medicine ​and they demonstrate an improved survival rate for male patients of 1.7-2.0 percentage points if they only receive donated blood from males. Moreover, the results suggest that more female patients will survive, if they only receive blood from one sex: i.e. only from men or only from women. 

For researchers in this area, it is not surprising that there is a difference between men’s and women's blood, explained Professor Pär I. Johansson. 

“Using new statistical methods, for the first time we can now demonstrate that the sex of blood donors is significant for those who receive the blood. The importance of the sex of donors has been debated by specialists for many years, although previous studies have not been able to demonstrate this effect. Our new knowledge can help us to improve patient survival after transfusions,” said Pär I. Johansson.

Around 1,000 more patients will survive

Every year, approximately 40,000 patients receive blood transfusions in Denmark. In round figures, 40% of blood is used in cancer treatment, 30% in births or operations and 30% to treat chronic diseases. 

As there are so many blood transfusions, even the smallest percentage improvements can have a huge clinical effect. According to the researchers behind the study, the results show that 650-800 more men and 200-300 more women could survive in Denmark every year, if hospitals can match transfusions on the basis of biological sex. 

In the wake of the new knowledge, the Blood Bank at Rigshospitalet is initiating a clinical study to investigate the effect of only giving men blood from male donors and giving women blood either exclusively from men or exclusively from women. Morten Bagge Hansen, a lead consultant at the Department of Clinical Immunology and the Blood Bank, explains: 

“Blood transfusions are an important and life-saving treatment. The new knowledge means we can optimise treatment. The clinical trial will start when the new IT system at the Blood Bank is launched early in the new year. We expect to find the same effect in the new study.” 

Towards personalised medicine

The research group behind the new results is conducting a number of other studies to make it possible to adjust blood treatment more specifically to the individual patient. Earlier this year, the research group published an article in the journal Blood on the useful life of blood during storage and the importance of this for patients treated with new and old blood, respectively. The study was based on the same methods and the same unique Danish patient data.

According to Professor Pär I. Johansson, sex-matching blood is considered as just one among a number of elements that can help improve treatment.

“Transfusion medicine is a complex area, because we are treating patients with a product from another living human being. The length of time in which blood is stored and the donor’s sex are both pieces in a complex jigsaw puzzle, and we will go on to study possible other factors that also affect patient survival,” said Pär I. Johansson.  

The study included approximately 90,000 patients, and the research results are based on a statistical method known as causal inference, which makes it possible to simulate large, randomised studies using machine learning and large data sets. 

The research was carried out at the Blood Bank at Rigshospitalet under the Center for Endotheliomics, which is a Clinical Academic Group (CAG) under Copenhagen Health Science Partners. Read more about the CAG here

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