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

Abstract

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.