Prognostic value of modified KDIGO staging for acute kidney injury in neonates: a prospective observational study in a level IIIB NICU

Background: Acute kidney injury (AKI) is an increasingly recognized complication in neonates admitted to intensive care, contributing significantly to short-term morbidity and mortality. Early diagnosis and risk stratification using standardized criteria such as modified neonatal Kidney Disease Improving Global Outcomes (KDIGO) remain critical, particularly in resource-constrained tertiary units. Limited Indian studies have evaluated AKI across both term and preterm neonates in Level IIIB Neonatal Intensive Care Unit (NICU) with post-discharge growth follow-up. Methods: This prospective observational study was conducted over one year (2023–2024) in a Level IIIB NICU. Renal-function tests were performed in 645 of 925 admissions (69.7%), and all neonates fulfilling modified neonatal KDIGO criteria were included. Demographic, clinical, biochemical, and therapeutic variables were analyzed; follow-up anthropometry was assessed six weeks after discharge. Multivariate regression identified independent predictors of AKI severity and mortality. Results: Among 925 admissions, 53 neonates met inclusion criteria for AKI, giving an incidence of 8.2%. Term neonates (56.6%) were more frequently affected than preterm. Stage 3 AKI carried the highest mortality (90%, p = 0.032). Sepsis (59%), shock (58%), and congenital heart disease (53%) were the major contributors. Inotropic support was required in 58.5% of cases. Nephrotoxic exposure occurred in 62%, predominantly to amikacin. Non-oliguric AKI was more common (70%). Post-discharge assessment showed that preterm small-for-gestational-age (SGA) infants achieved the greatest catch-up growth (38.5 g/day weight gain, 5 cm/month length velocity). The newly developed AKI risk score demonstrated an AUC of 0.81 (95% CI 0.74–0.88) for predicting severe AKI. Conclusion: The incidence of AKI in this Level IIIB NICU was 8.2%, with sepsis, shock, and congenital heart disease as predominant causes. The modified KDIGO criteria enabled early detection and accurate staging. Follow-up growth trends and quantified nephrotoxic exposure provide perspectives seldom addressed in prior Indian studies. Regular renal monitoring and risk-adjusted supportive care, coupled with longitudinal follow-up, are essential to improve neonatal outcomes. Trial registration: Clinical Trials Registry India, CTRI202306054119, 19/06/2023. Retrospectively registered.