Kidney injury in infants and children with iron-deficiency anemia before and after iron treatment

Background: Our study aimed to investigate the effects of iron-deficiency anemia (IDA) on renal tubular functions before and after iron treatment for infants and children with IDA. We measured urinary levels of two kidney injury markers: neutrophil gelatinase-associated lipocalin (NGAL) and liver-type fatty acid-binding protein (L-FABP).

Material and methods: Thirty-six infants and children with IDA and 20 matched healthy controls were included. We assessed different laboratory parameters, estimated glomerular filtration rate, urinary levels of NGAL, and L-FABP. Urinary kidney injury markers were measured in IDA patients before and after 3 months of oral iron therapy.

Results: IDA patients had significantly higher urinary NGAL and L-FABP levels compared to their healthy controls. After 3 months of oral iron treatment, there was a significant improvement (decrease) in urinary NGAL and L-FABP in infants and children with IDA. Urinary markers returned to normal levels (healthy control levels) in children with IDA, but not for infants with IDA compared to their healthy controls.

Conclusion: Subclinical kidney injury was found in infants and children with IDA. This injury was completely reversible in older children with IDA and partially reversible in infants with IDA after iron therapy. Higher urinary levels of kidney injury molecules in IDA infants after iron treatment are suggestive of more sensitivity of these infants to oxidative stress caused by iron therapy or may be due to the immaturity of the kidney and more damage caused by IDA which may require more time to recover.