Risk factors associated with a decreased estimated glomerular filtration rate based on cystatin C levels in school-age children with extremely low birthweight

Aim: A single centre retrospective cohort study was designed to investigate the estimated glomerular filtration rate (eGFR) in school-age children born with extremely low birthweight (ELBW) and to determine risk factors predictive of decreased eGFR.

Methods: We compared eGFR based on cystatin C (CysC-eGFR) between school-age children born with ELBW (ELBW group, n = 48; median gestational age: 26.9 weeks; median birthweight: 792 g) and children born at term (control group, n = 48). The ELBW group was then further divided into a decreased CysC-eGFR subgroup (eGFR <90 mL/min per 1.73 m² , n = 20) and a normal CysC-eGFR subgroup (n = 28), and perinatal background factors were compared.

Results: The ELBW group showed a significantly lower CysC-eGFR compared with the control group (P < 0.001). Comparison between the decreased and normal CysC-eGFR subgroups in the ELBW group showed that children with lower birthweight, shorter gestational age, lower 5-min Apgar score, longer length of mechanical ventilation, lower weight gain in the first 11 weeks, chronic lung disease, and postnatal corticosteroid administration had significantly decreased CysC-eGFR. Multivariate logistic regression showed that a lower 5-min Apgar score was the only independent risk factor for decreased CysC-eGFR.

Conclusions: CysC-eGFR might already be decreased at school age in children born with ELBW. Renal assessment in regular follow-up examinations is recommended.