The association between blood donor sex and age and transfusion recipient mortality: an exploratory analysis

BACKGROUND: There is recent support for long-term adverse effects of donor-recipient sex-mismatched red blood cell (RBC) transfusion, but short-term impact is unknown. A retrospective exploratory analysis was performed using data from a research database. METHODS: Adults admitted to hospitals in one Canadian center who received RBCs (2008-2014 [3 sites]; 2012-2014 [1 site]) were eligible. Patient data were extracted from a research database and donor data from the blood supplier. Cox regression models were used, with control of risk and confounding variables as covariates or using stratification. Exposure was defined by mutually exclusive categories. The outcome was in-hospital mortality. RESULTS: A total of 25,219 adults received 97,886 RBCs. Diagnoses included cardiovascular (28.8%), neoplastic (15.6%), traumatic (15.4%), or gastrointestinal (10.5%); 56.3% of transfused RBCs were male donors, and median donor age was 45 years (interquartile range, 30-54). Female patients exposed to male RBCs experienced a higher risk of in-hospital death (hazard ratio [HR], 1.31; 95% confidence interval [CI], 1.02-1.69; p = 0.038) compared to exclusive female RBC exposure. Exposure to RBCs from donors aged 45 years or younger was associated with a higher in-hospital death (HR, 1.21; 95% CI, 1.02-1.44; p = 0.026) compared to exclusive RBC exposure to donors older than 45 years. Donor-recipient sex-mismatched RBC exposure (vs. exclusively sex-matched) and RBC exposure from donors aged 45 years or younger (vs. exclusively RBCs from donors >45) were associated with increased mortality: sex-mismatched (HR, 1.23; (95% CI, 1.04-1.45; p = 0.017); donors aged 45 years or younger (HR, 1.21; (95% CI, 1.02-1.43; p = 0.031). CONCLUSION: Donor-recipient sex-matched RBC transfusions and transfusions from older donors may benefit patients.