Purpose: The objective was to identify the risk factors associated with nephrocalcinosis (NC) in preterm infants.
Methods: NC was diagnosed by renal sonography at 4 or 8 weeks of life, and 10 infants who had findings of type 3 or 4 NC were classified as the NC group. Various clinical and laboratory factors were compared between NC and control groups.
Results: Serum sodium (Na) on day 1, serum creatinine and fractional excretion of calcium (FeCa) at 1 and 2 weeks, and serum calcium (Ca), fractional excretion of sodium (FeNa), and urine Na on 2 weeks of life were significantly different between the two groups: the NC group showed significantly higher serum creatinine, FeNa, and FeCa than the control group, suggesting a greater decrease in renal function in the NC group. Differences of the laboratory findings disappeared after 4 weeks of life. The strongest risk factor was birth weight.
Conclusion: A transient decrease in renal function during the first 2 weeks of life was associated with development of NC in preterm very low-birth-weight infants, and the risk of NC increased as birth weight decreased.
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