Development of necrotizing enterocolitis after blood transfusion in very premature neonates

Background Prior studies report conflicting evidence on the association between packed red blood cell(PRBC)transfu-sions and necrotizing enterocolitis(NEC),especially in early weeks of life where transfusions are frequent and spontaneous intestinal perforation can mimic NEC.The primary objective of this study was to evaluate the association between PRBC transfusions and NEC after day of life(DOL)14 in very premature neonates.Methods A retrospective cohort analysis of very premature neonates was conducted to investigate association between PRBC transfusions and NEC after DOL 14.Primary endpoints were PRBC transfusions after DOL 14 until the date of NEC diagnosis,discharge,or death.Wilcoxon ranked-sum and Fisher's exact tests,Cox proportional hazards regression,and Kaplan-Meier curves were used to analyze data.Results Of 549 premature neonates,186(34%)received transfusions after DOL 14 and nine(2%)developed NEC(median DOL=38;interquartile range=32-46).Of the nine with NEC after DOL 14,all were previously transfused(P<0.001);therefore,hazard of NEC could not be estimated.Post hoc analysis of patients from DOL 10 onward included five additional patients who developed NEC between DOL 10 and DOL 14,and the hazard of NEC increased by a factor of nearly six after PRBC transfusion(hazard ratio=5.76,95%confidence interval=1.02-32.7;P=0.048).Conclusions Transfusions were strongly associated with NEC after DOL 14.Prospective studies are needed to determine if restrictive transfusion practices can decrease incidence of NEC after DOL 14.