Age and blood transfusion: relationship and prognostic implications in cardiac surgery

Background: Red blood cell (RBC) transfusion is a well-known predictor of acute kidney injury (AKI) and death after cardiac surgery. This study aimed to define the relationship between age and the need for RBC. Methods: Study population included 1,765 consecutive patients undergoing on-pump procedures from 2013 to 2015. The relationship between RBC transfusion and both survival and AKI, and any interaction with age was estimated. A propensity score for the likelihood to receive RBC transfusion was calculated using multivariate logistic regression analysis to adjust for the effect of confounding factors. A logistic estimation curve was developed to investigate the interaction between this score and age. Results: Patients receiving RBC transfusions had more comorbidities irrespective of age. Elderly patients underwent transfusion more often than younger patients with a 1.3-fold increase in the relative risk for transfusion. Age did not independently predict the need for RBC. AKI and mortality rates were significantly higher in transfused subsets irrespective of age. Conclusions: Comorbidity profile and not age per se confers an increased risk of transfusion.