dos Santos et al. undertook a cohort study of 1077 consecutive prematures with birth weight < 1500 g admitted into eight Brazilian neonatal intensive care units (NICUs); 574 (53.3%) received at least one red blood cell (RBC) transfusion during their hospital stay. Neonates with congenital anomalies were excluded. The hypothesis was: “RBC transfusions in very low birth weight preterm infants are independently associated with an increase in intra-hospital mortality rates”. The relative risk of death during hospital stay was indeed 1.49 (95%CI: 1.17-1.78, p = 0.001) in transfused patients, and the relative risk of death after 28 days of life was 1.89 (95%CI: 1.19-2.69, p = 0.01).
The fact that there is an association between an independent variable like RBC transfusions and an outcome like mortality does not mean that there is a cause-effect relationship. This is well recognized by the authors. More randomized clinical trials must be conducted to better study the efficacy and safety of RBC transfusions given to preterm infants.
– Jacques Lacroix