Analysis of clinical characteristics of necrotizing enterocolitis in term infants

Objective To investigate the characteristics and outcomes of necrotizing enterocolitis (NEC) in Chinese term infants population. Methods A national neonatal necrotizing enterocolitis network was established. Neonates as having necrotizing enterocolitis with gestation age ≥37 weeks were identified if they met the accepted diagnostic criterion during the study period from Jan 1st 2011 to Dec 31st 2011. The data of maternal and neonates' characteristics, the comorbidities, the clinical interventions prior to NEC, the clinical courses and radiology results, the medical and surgical treatment and the outcomes were collected. SPSS 19.0 software was used to do statistic analysis. Logistic-regression models were used to analyze the risk factors for death in infants with NEC, odds ratio (OR) and 95% confidence interval (CI) were calculated. Results There were 231 067 newborn infants, 164 307 of them were term infants, admitted to 95 hospitals in main land China. There were 718 term infants were diagnosed as necrotizing enterocolitis with the incidence of 0.44%. There were 294 term infants cases identified as ≥stage 2 necrotizing enterocolitis for the analysis, including 193 cases of stage 2 and 101 cases of stage 3.The mean gestation age was (39.0±1.3) weeks, and the mean birth weight was(3 087.4±548.3)g. The percentage of small for gestation age was 20.4%. The onset age of NEC was 5 (2-11)d. The percentage of cases received breast milk feeding was 23.7%. The most common comorbidities were sepsis (9.5%, 28/294), asphyxia (9.5%, 28/294), pneumonia (7.8%, 23/294) and congenital megacolon (7.5%, 22/294). The bowel perforation rate was 13.9%. The rate of cases who received surgical treatment was 25.2%(76.6% small intestinal necrosis and 65.8% small intestinal perforation). The mortality rate was 28.9%(the mortality rate were 20.7% and 44.6% in stage 2 and stage 3 NEC, respectively). Noninvasive continuous positive airway pressure treatment for NEC (OR=5.278, 95% CI: 2.058-13.533, P<0.01) and NEC staging 3 (OR=3.156, 95% CI: 1.766-5.642, P<0.01) were statistically significantly associated with mortality of NEC. Conclusions The term infants with necrotizing enterocolitis usually have the underlying comorbidities. The breastmilk feeding rate is low. Necrotizing enterocolitis remains high mortality in term neonates in Chinese neonatal units. Noninvasive continuous positive airway pressure treatment for NEC is statistically significantly associated with mortality of NEC. Key words: Term birth; Infant, Newborn; Enterocolitis, necrotizing; Mortality; Risk factors