Association of neutrophil to lymphocyte ratio with preterm necrotizing enterocolitis: a retrospective case-control study

Abstract

Background: There have been few studies on the relationship between the neutrophil to lymphocyte ratio (NLR) and necrotizing enterocolitis (NEC). We conducted a retrospective case-control study to investigate this relationship in preterm neonates. Methods: A total of 199 preterm neonates diagnosed with NEC between January 2018 and January 2020 were included in this study. For each preterm infant with NEC that was admitted to the neonatal intensive care unit (NICU), controls were preterm neonates (matched for gestation and year of birth) who were not diagnosed with NEC. Exclusion criteria were post-maturity, small or large for gestational age (week of pregnancy), congenital major anomalies, and cyanotic congenital heart disease. Univariate and multivariate logistic regression analyses were used to identify the association between NLR and preterm NEC. Results: This study included 93 preterm neonates with NEC and 106 matched controls. There were no significant differences in gestational age (GA), birth weight (BW), age, sex, vaginal delivery (VD), chorioamnionitis (CA), and gestational diabetes mellitus (GDM) between the groups. Compared with the control group, the lower and higher NLR levels in the NEC group were statistically different. Following univariate analysis, NLR was a risk factor for NEC (odds ratio [OR], 1.40; 95% confidence interval [CI], 1.00–1.90; P = 0.042), and according to multivariate analysis, risk factors for NEC were NLR ≥ 3.20 and NLR < 1.60, within 1 week before NEC diagnosis. Thus, NLR values of ≥ 1.60 and < 3.20 were determined as the predictive cut-off values for protecting preterm infants from NEC (Model I: OR, 0.20; 95% CI, 0.10–0.40; P < 0.001) and (Model II: OR, 0.10; 95% CI, 0.00–0.40; P < 0.001]. Conclusions: NLR ≥ 1.60 and NLR < 3.20 were associated with a decreased risk of NEC in preterm infants.