Early detection of kidney impairment in school-aged children born very preterm: a parallel use of traditional and modern biomarkers.

BACKGROUND

Prematurity has been linked to kidney dysfunction from infancy through adulthood. Children born very preterm are at particular risk due to interrupted nephrogenesis. However, early detection remains challenging, and a uniform monitoring strategy is lacking.

METHODS

This cross-sectional study involved school-aged (6-16 years) children born at ≤ 32 weeks of gestation, with no history of small for gestational age (SGA). They were further stratified by birth weight (BW): low, very low, and extremely low (LBW, VLBW, ELBW) categories. Age- and sex-matched full-term children served as controls. Anthropometry, blood pressure (BP), and kidney function were assessed, using traditional (urea; creatinine, Cr; β2-microglobulin, B2M; albuminuria) and modern biomarkers (cystatin C, CysC; symmetric dimethylarginine, SDMA). Estimated glomerular filtration rate (eGFR) based on Cr and Cr-CysC was also calculated. Statistical analysis was performed using R (version 4.3.2), with significance set at p < 0.05.

RESULTS

Eighty-one children were included: 43 preterm (77% from multiple pregnancies) and 38 controls. Compared to controls, preterm participants had higher serum cystatin C (p < 0.001) and lower Cr-CysC-eGFR (p < 0.001). They also had higher serum urea (p = 0.002), but all individual values were within the normal range. No differences were observed in BP, serum Cr, Cr-eGFR, or albuminuria. ELBW children had lower body mass index (BMI) (p = 0.048) and higher B2M (p = 0.046) than LBW peers.

CONCLUSIONS

School-aged children born very preterm may already exhibit subtle signs of kidney dysfunction, with ELBW children showing greater metabolic and renal strain. Cystatin C and Cr-CysC-eGFR appear promising biomarkers for early detection of kidney alterations in this high-risk population.