Most common blood type trebles death risk

Classification O shared by half of Britons does not clot as well as types A, B or AB, say scientists

HAVING blood type O almost trebles the risk of dying from serious injury because it does not clot as well, scientists in Japan have discovered.

Data there showed a death rate of 28 per cent for those with type O blood. The death rate of patients from other blood groups combined was 11 per cent. Dr Wataru Takayama, the lead researcher in the study conducted at Tokyo Medical and Dental University Hospital, said: “Recent studies suggest that blood type O could be a potential risk factor for haemorrhage.

“Loss of blood is the leading cause of death in patients with severe trauma but studies on the association between different blood types and the risk of trauma death have been scarce.

“We wanted to test the hypothesis that trauma survival is affected by differences in blood types.”

Nearly half the UK’S population is type O, making it the most common blood group. Blood type is determined by proteins on the surfaces of red blood cells.

The other main blood group categories are A, B and AB – 42 per cent of the population are type A, 8 per cent type B and 3 per cent type AB. Type O blood can generally be donated to anyone, with no ill-effects, whereas someone with type A blood can only donate to someone who is type A or type AB; someone with type B blood can only donate to someone who is type B or type AB; and someone with type AB blood can only donate to someone else who is type AB.

However, people with type O have lower levels of Von Willebrand factor, a blood clotting agent that helps prevent life-threatening bleeding.

The researchers suggested that a lower level of the factor could be a possible explanation for the higher death rate in trauma patients with blood type O. Dr Takayama said the results raised questions about the emergency transfusion of type O red blood cells to severe trauma patients – victims of injuries with the potential to cause long-term disability or death.

He said: “Our results also raise questions about how emergency transfusion of O type red blood cells to a severe trauma patient could affect homeostasis, the process which causes bleeding to stop, and if this is different from other blood types.

“Further research is necessary to investigate the results of our study and develop the best treatment strategy for severe trauma patients.”

All the study’s 900 participants had suffered severe trauma and been admitted to critical care medical centres in Japan between 2013 and 2016.

The researchers warned that all the patients whose data was analysed in this study were Japanese, so there was a need for further research to see if the findings applied to other ethnic groups.

The research was reported in Critical Care, the official journal of the World Federation of Societies of Intensive and Critical Care Medicine.