Photo by Elise Amendola
Blood for transfusion
Having type O blood is associated with high death rates in severe trauma patients, according to a study published in Critical Care.
Researchers found that severe trauma patients with type O blood had a death rate of 28%, compared to a rate of 11% in patients with other blood types.
“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,” said study author Wataru Takayama, of Tokyo Medical and Dental University Hospital of Medicine in Japan.
“We wanted to test the hypothesis that trauma survival is affected by differences in blood types.”
To do this, the researchers evaluated the medical records of 901 patients with severe trauma who had been transported to either of 2 tertiary emergency critical care medical centers in Japan from 2013 to 2016.
Most patients had type O (n=284, 32%) or type A blood (n=285, 32%), followed by type B (n=209, 23%) and type AB (n=123, 13%).
The mortality rate was significantly higher in patients with type O blood than in patients with the other blood types—28% and 11%, respectively (P<0.001).
In a multivariate analysis, mortality was significantly higher for patients with type O blood. The adjusted odds ratio was 2.86 (P<0.001).
Patients with type O blood have been shown to have lower levels of von Willebrand factor than patients with other blood types. The researchers suggested that a lower level of von Willebrand factor is a possible explanation for the higher death rate in trauma patients with blood type O.
“Our results also raise questions about how emergency transfusion of O type red blood cells to a severe trauma patient could affect homeostasis . . . and if this is different from other blood types,” Dr Takayama said.
“Further research is necessary to investigate the results of our study and develop the best treatment strategy for severe trauma patients.”
In particular, further research is needed to determine if the findings from this study apply to other ethnic groups, as all the patients in this study were Japanese.
In addition, the researchers didn’t evaluate the impact of the individual blood types A, AB, or B on severe trauma death rates. They only compared type O to non-O blood types, which may have diluted the effect of individual blood types on patient survival.