Acute kidney injury in infants with necrotising enterocolitis: A case-control study

Necrotising enterocolitis (NEC) is a leading cause of morbidity and mortality in preterm infants. Acute kidney injury (AKI) is increasingly recognised as a common complication in this population, yet its relationship with NEC remains under-characterised. We sought to evaluate the incidence of AKI in infants with NEC and examine its association with NEC severity (using Bell staging) in a tertiary neonatal intensive care unit (NICU).

A retrospective 1:2 case-control study was conducted in a single tertiary NICU between October 2018 and October 2023. Forty-nine preterm infants diagnosed with NEC were matched to 100 controls based on birth weight, gestational age, and gender. AKI was defined using modified neonatal KDIGO criteria, incorporating both serum creatinine and urine output.

AKI was identified in 25 of 149 infants (16.8%), with an incidence among those with NEC of 30.6% compared to controls (10%). NEC exposure was associated with increased odds of AKI in our cohort when controlling for patent ductus arteriosus (PDA), birth weight, gentamicin and ibuprofen receipt, with an adjusted odds ratio (OR) of 3.6 (95% CI 1.3-10.2, p = 0.0129). Among NEC cases, AKI onset occurred a median of two days after diagnosis. No association was found between Bell stage and AKI incidence, albeit with a small sample size. Mortality in the NEC-AKI group was 60%, compared to 20.6% in NEC infants without AKI.

NEC is associated with increased risk of AKI in preterm infants, when controlling for birth weight, gestational age PDA, ibuprofen and gentamicin exposure. Bell stage was not associated with AKI incidence, in our cohort. These findings support the consideration of early kidney function surveillance in NEC to inform risk stratification and improve outcomes.

• NEC is a leading cause of morbidity in preterm infants, often triggering systemic inflammation and multiorgan dysfunction. AKI is common in neonates and associated with poor outcomes, but its relationship with NEC is not well defined.  What is New: •  In our cohort, NEC is associated with increased risk of AKI in preterm infants, when controlling for birth weight, gestational age, PDA, ibuprofen, and gentamicin exposure. NEC-associated AKI is linked to higher mortality. Consideration for routine surveillance for AKI in infants with NEC warrants further study.