Real-world modality selection and outcomes in neonatal kidney replacement therapy: a single-center cohort study.

UNLABELLED: To describe biochemical and clinical outcomes of peritoneal dialysis (PD) and continuous kidney replacement therapy (CKRT) in neonates requiring kidney replacement therapy (KRT), and to identify factors associated with mortality. This retrospective single-center study included neonates who underwent KRT between January 2013 and December 2025. Patients were grouped as PD, CKRT, or sequential PD + CKRT. Demographics, indications, biochemical response, complications, and outcomes were analyzed. Eighty-five neonates were included: 42 (49%) PD, 23 (27%) CKRT, and 20 (24%) sequential PD + CKRT. PD patients had lower gestational age and birth weight than CKRT patients (p < 0.05). Acute kidney injury (AKI) was the most common indication overall, whereas inborn errors of metabolism predominated in the CKRT group (61%). CKRT achieved greater early reductions in blood urea nitrogen, creatinine, and ammonia/leucine within 24 h (all p < 0.05); however, end-of-treatment biochemical outcomes were similar between modalities. Treatment duration was shorter with CKRT (p < 0.001), while hospital stay and survival were comparable. Non-survivors had lower birth weight, more frequent invasive mechanical ventilation, higher rates of AKI, and higher complication rates (p < 0.05). In multivariable analysis, the presence of KRT-related complications was the only variable independently associated with mortality (OR 12.69, p = 0.024). CKRT use increased over time (26% vs. 44%), with a non-significant increase in survival (25% to 60%, p = 0.193). CONCLUSION: CKRT and PD achieved acceptable outcomes when selected according to patient characteristics and clinical needs. KRT-related complications were independently associated with mortality, likely reflecting illness severity, rather than a direct causal effect. Multicenter studies are needed to define modality selection in KRT. WHAT IS KNOWN: • Neonatal kidney replacement therapy (KRT) is a lifesaving intervention in critically ill infants. • Peritoneal dialysis (PD) has traditionally been used more frequently due to its technical feasibility in small infants. • Continuous kidney replacement therapy (CKRT) provides more rapid solute clearance but is more complex to implement. WHAT IS NEW: • PD and CKRT achieved acceptable outcomes when selected according to patient characteristics and clinical needs. • KRT-related complications were independently associated with mortality (OR 12.69, p = 0.024); however, this association should be interpreted with caution given potential confounding by illness severity, rather than a direct causal effect.