Early postoperative measurement of fibroblast growth factor 23 predicts severe acute kidney injury in infants after cardiac surgery

Aims: Acute kidney injury (AKI) occurs in 30 – 40% of children after cardiac surgery (CS) and is associated with poor prognosis. Fibroblast growth factor 23 (FGF23) is a bone-derived hormone with a pivotal role in phosphorus and vitamin D metabolism. We assessed FGF23 as an early marker for severe AKI (sAKI) in infants after CS. Materials and methods: Samples were previously collected in a multicenter observational study from children after CS. Serum FGF23 (n = 41) and urine AKI biomarker levels (n = 35) were assessed 4 – 8 hours after bypass. sAKI was defined as ≥ 100% rise in serum creatinine over baseline. Non-parametric and ROC analyses were used to evaluate the association between FGF23, urine AKI markers, and sAKI in the week after CS. Results: Serum FGF23, urine NGAL, and urine KIM1 were higher in sAKI patients. The AUC-ROC for urine NGAL (0.74, [0.49 – 0.99]), urine KIM1 (0.79, [0.68 – 0.98]), and serum FGF23 (0.74, [0.5 – 0.9]) showed fair prediction of sAKI. Conclusion: Early measurement of FGF23 has predictive ability in infants who develop sAKI after CS with cardiopulmonary bypass.