Growth during the first 3 postnatal months in infants with congenital kidney failure (CKF) requiring renal replacement therapy (RRT)

Background: With advanced technology, survival of neonates with congenital kidney failure (CKF) requiring kidney replacement therapy (KRT) has improved. Nutrition is essential but difficult to attain as KRT removes proteins and micronutrients, and these children often have multiple co-morbidities. Scant data exist to guide clinicians on appropriate energy requirements for growth. Methods: We performed a retrospective study of infants with severe CKF admitted to Children’s of Alabama between 2016 - 2022 who required KRT within 10 days. We evaluated risk factors and growth in the 18/24 (75%) infants who survived to 90 days. Our primary and secondary outcomes were length z-score ≥-2 vs. <-2 at 90 days and weight z-score ≥-2 vs. <-2 at 90 days, respectively. Demographics, comorbidities, KRT Dose Eras (1-body surface area (2000/1.73/m ² /hr) vs. 2-weight-based era (24mL/kg/hour)) and Nutrition Era 1 vs. 2 were evaluated. Results: At 90 days, 7/18 (38.9%) had length z-score ≥- 2 while 10/18 (55.6%) had a weight z-score ≥-2. Risk factors for weight z-score ≥- 2 include time to PD transition. Risk factors for length z-score ≥- 2 included Era with higher calorie and protein goal targets (both p< 0.01) and CKRT clearance in Era 2 had better z-scores for weight. Conclusion: Malnutrition in neonates with CKF is high. More studies are needed to better understand optimal strategies to assure adequate growth. Until then, we recommend 24ml/kg/hr clearance dose and at least 130kcal/kg/day and 4g/kg/day amino acids to start in neonates with CKF on KRT.