Long-term renal follow up of preterm neonates born before 35 weeks of gestation.

BACKGROUND: The hypothesis of the Developmental Origins of Health and Disease states that environmental factors during fetal and infantile life are risk factors for some chronic diseases in adulthood. Few studies, however, have confirmed this hypothesis early in childhood. Therefore, we assessed how premature birth and low-birthweight (LBW) affect the renal function of Japanese children. METHODS: This retrospective study surveyed 168 patients who were born before 35 weeks of gestation and were cared for at the present neonatal intensive care unit. Follow-up duration was >2 years. Serum creatinine (sCr) and estimated glomerular filtration rate (eGFR) recorded in medical records were reviewed. RESULTS: The eGFR at 2 years of age was significantly correlated with birthweight and gestational age (P < 0.01). Approximately 10.7% of the children had low eGFR (<90 mL/min/1.73 m2 ) without clinical symptoms or abnormal urine examination. These children had high sCr on day 7 after birth (P < 0.01) and delayed recovery of these levels during the first month after birth. CONCLUSION: Premature gestational age and LBW directly affect renal function in young children. High sCr on day 7 after birth is a risk factor for chronic kidney disease in children. Careful follow up of renal function is therefore required for premature infants and infants with LBW beginning in early childhood to prevent renal dysfunction.