Neonatal acute kidney disease in the NCCHD-neoAKI Cohort: risk factors and prognostic outcomes

Background: Acute kidney disease (AKD) is defined as kidney dysfunction lasting 7–90 days after an initiating event. Although widely recognized in adults and children, its significance in neonates is unclear. We aimed to investigate the risk factors and outcomes of neonatal AKD in a cohort of neonates with acute kidney injury (AKI). Methods: We performed a retrospective cohort study at a tertiary NICU in Japan. Among 345 neonates with AKI between 2014 and 2024, 280 were included after excluding cases with congenital kidney disease, early death (< 7 days), or missing data. AKD was defined by KDIGO/ADQI criteria. We compared clinical features and outcomes between neonates with and without AKD and used multivariable logistic regression to identify predictors. Results: Of 280 neonates with AKI, 85 (30%) developed AKD. Compared to non-AKD neonates, those with AKD had higher 90-day mortality (8% vs. 2%, P = 0.005) and MAKE90 (17% vs. 7%, P = 0.014). Chronic lung disease (78% vs. 50%, P < 0.001) and intraventricular hemorrhage (38% vs 16%, P = 0.002) were also more common in the AKD group. In multivariable analysis, aminoglycoside exposure (OR = 2.04; 95% CI, 1.07–4.04; P = 0.031) and lower birth weight (per 100 g) (OR = 2.73; 95% CI, 1.11–1.22; P = 0.002) were independently associated with AKD. Conclusion: Neonatal AKD was common and associated with increased mortality and major adverse kidney events. Our findings support AKD as a useful concept for identifying high-risk neonates and highlight the need for long-term kidney monitoring in this vulnerable population.