This is an observational pilot study to enhance understanding of the pathophysiology and epidemiology associated with effects of AKI in premature infants and the role that neonatal AKI plays in future development of CKD. In eligible preterm infants, blood and urine samples will be collected at pre-specified time points during hospitalization and at outpatient follow-up appointments at 6 months, 1 year, 2 years, and 5 years of age and stored in the biorepository. Blood pressure will be measured and recorded at NICU discharge and at all follow-up visits. A renal ultrasound will be performed to monitor renal growth at 2 and 5 years of age. All data will be entered into a comprehensive clinical database, including laboratory results.
