Risk factors for necrotizing enterocolitis in preterm infants: how race, gender, and health status contribute

Abstract

Purpose: To examine 5 infant characteristics and health factors that might be risk factors for necrotizing enterocolitis (NEC) in preterm infants.

Subjects: One hundred thirty-four preterm infants at high risk for NEC because of either having a birth weight of <1500 g or requiring mechanical ventilation at birth.

Design: Descriptive secondary analysis using data from a larger longitudinal study.

Methods: Weekly review of infants' medical record until discharge; demographic questionnaire completed by mothers at the time of enrollment; and data analysis done with logistic regression, Fischer's exact tests, and correlations.

Outcome measures: Total number of days the infant required mechanical ventilation, birth weight in grams, number of infections prior to NEC diagnosis, maternal race (black, white, or Asian), and infant gender were used to predict the development of NEC.

Results: Maximum likelihood estimates indicated that mechanical ventilation had a positive relationship with developing NEC, such that as the number of days of mechanical ventilation increased so did the risk of developing NEC. There was also a very strong positive relationship between the number of nosocomial infections and NEC, indicating that as the number of infections increased, the likelihood of developing NEC increased. Although the relationship between race and NEC was not significant in the logistic regression, the Fisher exact test showed that black preterm infants had increased incidence of NEC as compared with other races. This relationship was not due to correlations between race and mechanical ventilation or infections. No relationship between gender and NEC was noted. Birth weight was not significantly associated with NEC in the logistic regression but was correlated with NEC, probably because of its correlation with mechanical ventilation and number of infections.

Conclusions: In this sample, number of infections and length of mechanical ventilation were the primary predictors of NEC in preterm infants. In addition, the frequency that black infants are diagnosed with NEC is significantly higher than that of other races. Knowledge of risk factors for NEC can allow healthcare providers to evaluate and adjust care practices for preterm infants who present with higher risk for NEC on the basis of empirical data.