Using Classification Tree Analysis to Predict the Type of Infection in Preterm Neonates: Proof of Concept Study

Biomarker Potential of Interleukin-6 in Differentiating Necrotizing Enterocolitis from Late-Onset Sepsis in Neonates Born Preterm

Objective

Interleukin-6 (IL-6) is an early biomarker for sepsis and necrotizing enterocolitis (NEC). We assessed IL-6's ability to differentiate between late-onset sepsis (LOS) and NEC and between medical and surgical NEC.

Study design

This retrospective cohort study included infants born preterm (birth weight <1500 g, gestational age <32 weeks) with ≥1 episodes of suspected late-onset sepsis (sLOS) between 2018 and 2023. Plasma IL-6 levels at sLOS onset were analyzed. Infants were grouped into (1) control (no sepsis/NEC), (2) LOS (culture negative/positive sepsis), or (3) NEC (medical/surgical), on the basis of the greatest classification of their observed episodes. IL-6's predictive value (alone and in combination with C-reactive protein) for sLOS outcomes was assessed with receiver operating characteristic analysis, with the area under the curve (AUC) quantifying its discriminative quality.

Results

sLOS was observed in 421 infants (670 episodes); 131 (31%) had no LOS or NEC, 225 (53%) had LOS without NEC, and 65 (15%) had NEC. Median IL-6 values significantly differed between all groups, with highest in infants with NEC. The odds of NEC over LOS increased by a factor of 1.53 (95% CI 1.42-1.65, P < .001) for every doubling of IL-measurements. IL-6 was not associated with the odds of surgical NEC compared with medical NEC. IL-6's ability to distinguish NEC from LOS was moderate (AUC 0.73). IL-6 combined with C-reactive protein (AUC 0.64) showed poor discriminative ability.

Conclusions

Although elevated IL-6 levels are associated with greater odds of having NEC instead of LOS, the moderate predictive value suggests that IL-6 alone may not be sufficient for accurate early diagnosis or differentiation.

Diagnosis of Neonatal Sepsis: The Role of Inflammatory Markers

This is a narrative review on the role of biomarkers in the diagnosis of neonatal sepsis. We describe the difficulties to obtain standardized definitions in neonatal sepsis and discuss the limitations of published evidence of cut-off values and their sensitivities and specificities. Maternal risk factors influence the results of inflammatory markers as do gestational age, the time of sampling, the use of either cord blood or neonatal peripheral blood, and some non-infectious causes. Current evidence suggests that the use of promising diagnostic markers such as CD11b, CD64, IL-6, IL-8, PCT, and CRP, either alone or in combination, might enable clinicians discontinuing antibiotics confidently within 24-48 h. However, none of the current diagnostic markers is sensitive and specific enough to support the decision of withholding antibiotic treatment without considering clinical findings. It therefore seems to be justified that antibiotics are often initiated in ill term and especially preterm infants. Early markers like IL-6 and later markers like CRP are helpful in the diagnosis of neonatal sepsis considering the clinical aspect of the neonate, the gestational age, maternal risk factors and the time (age of the neonate regarding early-onset sepsis) of blood sampling.