Higher Donor Body Mass Index is Associated with Increased RBC Hemolysis

Red blood cell (RBC) donor characteristics, collection, processing, storage, and transfusion have been well studied, but how the factors interact to affect the clinical outcome transfusions is not well understood.  Several studies have accessed RBC storage time but have not found clinical evidence that fresh RBCs are superior to RBCs stored for longer time periods.  Two papers recently published in TRANSFUSION, however, found that donor body mass index (BMI) is associated with increased hemolysis of RBCs.  Sparrow et al analyzed 1734 leukoreduced RBC donations (52.6% male) from the Australian Red Cross Blood Service.  They found that that the samples from male donors had a larger volume, higher hemoglobin, and higher hemolysis than samples from female donors.  Based on multivariable linear regression, increasing BMI was associated with increased hemolysis for all donors with the strongest association seen among male donors with the highest BMI (BMI >30 kg/m²) (odds ratio 4; 95% C.I., 1.8 to 8.6).  A second study found similar results analyzing blood donors from the U.S. National Heart, Lung, and Blood Institute REDS-III study (n=13,317).  Furthermore, transfusion of RBCs stored for 42 days from donors with higher BMI (>30 kg/m²) led to lower post-transfusion RBC recovery in immunocompromised mice 10 minutes after transfusion than RBCs from donors with lower BMIs (P=0.026).  Further investigations into factors affecting the quality of RBCs and clinical transfusion outcomes are needed.

References:

1. Hazegh K, Fang F, Bravo MD, Tran JQ, et al. Blood donor obesity is associated with changes in red blood cell metabolism and susceptibility to hemolysis in cold storage and in response to osmotic and oxidative stress.  Transfusion 2021; 61; 435-448. 
2. Sparrow RL, Payne KA, Adams GG. Higher donor body mass index is associated with increased hemolysis of red blood cells at 42-days of storage:  a retrospective analysis of routine quality control data.  Transfusion 2021; 61; 449-463. 
3. Shopsowitz KE and AW Shih. How red cell quality is starting to carry its weight.  Transfusion 2021; 61; 336-339.