Late complications of the gastrointestinal system in preterm babies are increasing along with early pulmonary and cardiologic early complications. NEC remains a disease with high mortality even with aggressive treatment12)
. Additionally, NEC requiring surgical treatment lead to growth and developmental disorders in VLBW infants13
. The incidence of NEC varies with reporters. According to Walsh and Kliegman15)
, Gregory et al.16)
, Egan et al.17)
, and Polin et al.18)
, NEC occurs in 0.83% to 7.5% of all infants, but according to Kliegman et al.19)
the incidence of VLBW infants admitted to the NICU is 12%. In this study, the incidence of NEC among the VLBW preterm infants was 10%, which was similar to other reports.
The etiology and pathogenesis of NEC is not clearly understood20)
, but it is known to be a complex, multifactorial disease21
. According to a recent reports transfusion increase the risk for NEC7)
, and the NEC mechanism is related to a recent exposure to transfusions. The latest hypotheses as to why packed RBC(t) increases the risk of NEC suggest that stored RBCs decrease nitric oxide23)
and a packed RBC(t) increases the intestinal immune response24)
. In this study, GA and B.wt were not different between the NEC and control groups, but in the univariate logistic regression, the risk for NEC decreased significantly the higher the GA, B.wt, and Apgar scores at 1 and 5 minutes. Higher PDA incidences also tended to increase NEC risk, but the difference was not significant. The number of patients in the NEC group who were diagnosed within 48 hours of a transfusion was 14 and after 48 hours the number was two. Only two patients with NEC did not receive a transfusion their GA were 31 and 30 weeks and their Apgar scores at 1 minute were 1 point and 0 points. Cardiopulmonary resuscitation was carried out on these infants. The Apgar score at 5 minutes recovered to 5 points for both and the infants recovered with conservative therapy after the NEC diagnosis.
In the multivariate logistic regression, a higher frequency of RBC(t) before the NEC diagnosis increased the risk for NEC 1.63 times (95% CI, 1.145 to 2.305; P
=0.007) after adjusted for GA, Apgar score at 1 minute, RDS, PROM, DIC, and death. The number of transfusions was significantly different between our two groups and the adjusted multivariate logistic regression revealed that the NEC risk increased 1.297 times (95% CI, 1.097 to 1.533; P
=0.002) with an increase in the number of transfusions. There are several biologically plausible reasons why packed RBC(t) may lead to NEC, including a decrease in nitric oxide in stored RBCs and an exaggerated intestinal immune response to packed RBC(t)9)
. In contrast to our study, Josephson et al10)
. reported that RBC(t) had no temporal relationship to NEC and stated that is only meaningful as it indicates the infant's general condition.
Because many reports are contradictory on the relationship between transfusions and NEC, additional studies are necessary involving larger patient groups. In addition, the patient's general condition and the risk of NEC based on the transfusion must be considered when treating preterm infants <1,500 g.
In conclusion, we analyzed the risk factors for developing of NEC in VLBW preterm infants. The results showed that the risk for NEC increased with an increased frequency of transfusions before the NEC diagnosis (relative risk, 1.63; 95% CI, 1.145 to 2.305; P=0.007).