No Temporal Association Between RBC Transfusions and NEC in Extremely Low-Birthweight Infants, Study Suggests

Among extremely low-birthweight (ELBW) infants, red blood cell transfusion was not temporally associated with a higher risk of necrotizing enterocolitis (NEC) during 72-hour post-transfusion hazard periods compared with control periods.  Investigators published the secondary analysis of the Transfusion of Prematures (TOP) trial May 3 in JAMA Network Open.

NEC, a life-threatening gastrointestinal disease, contributes to 10% of neonatal mortality and poses significant risks of severe morbidity among survivors. Previous observational and preclinical studies have suggested a link between anemia, RBC transfusions and NEC, while others have yielded conflicting results. The TOP trial, the largest randomized clinical trial to compare transfusion thresholds in ELBW infants to date, found no significant difference in NEC rates between higher and lower transfusion threshold groups but did not examine the temporality of NEC after RBC transfusion.

This secondary analysis included 1,690 ELBW infants at risk of NEC between postnatal day 10 and 60. Researchers identified 4,947 hazard periods and 5,813 control periods. Among the 133 infants who developed NEC, 44.4% occurred during hazard periods and 55.6% during control periods (11.9 versus 12.7 per 1,000 periods, respectively). Primary analyses revealed no significant differences between higher and lower hemoglobin threshold groups. However, during postnatal days 20 to 29, infants in the lower transfusion threshold group had a significantly higher risk of NEC during hazard periods compared with control periods (adjusted risk ratio, 2.17). Researchers noted the need for further investigation with larger sample sizes to confirm this finding.

While the results suggest no association between severe anemia and NEC after RBC transfusion, the authors noted that the results might not be applicable to infants with hemoglobin values falling beyond the parameters outlined in the TOP trial (7-10 g/dL). They emphasized the possibility that a lower hemoglobin threshold could increase the NEC rate due to more severe anemia, as the trial prevented severe forms of anemia often associated with a higher risk of NEC.