Is "transfusion-associated necrotizing enterocolitis" an authentic pathogenic entity?

BACKGROUND: Necrotizing enterocolitis (NEC) sometimes occurs after a transfusion, but it is unclear whether this is a chance association or cause and effect. STUDY DESIGN AND METHODS: We compared features of neonates that developed surgical NEC within 48 hours after transfusion with others that developed NEC not preceded by transfusion. We assessed the blood used for transfusion and feeding practices among NEC cases and controls. RESULTS: Forty neonates developed surgical NEC after a transfusion and 72 developed NEC unrelated to a transfusion. Those with NEC after transfusion were born at earlier gestation (mean 27 weeks, 90% confidence interval [CI] 26-28 years vs. mean 30, 90% CI 29-31; p < 0.001) and were of lower birth weight (mean 981 g, 90% CI 835-1128 g vs. mean 1371 g, 90% CI 1245-1496; p < 0.001) and developed NEC later during their neonatal intensive care unit course (day of life: mean 23, 90% CI 20-27 vs. mean 16, 90% CI 13-19; p < 0.001). Transfusions were more prevalent among those that developed NEC (p < 0.001). The blood transfused to those that developed NEC was not older, but those who developed NEC had been fed larger volumes of milk in the 24 hours before and during transfusion (p = 0.04) and were more likely to have been fed a bovine product during that period (p = 0.004). CONCLUSION: Approximately one-third of surgical NEC cases in our system occurred after a transfusion. We speculate that a target area for reducing the prevalence of posttransfusion NEC involves feeding practices immediately before and during RBC transfusion.