Bai Z, et al. - Experts compared the Fibroblast growth factor 23 (FGF23) and insulin-like growth factor binding protein 7 (IGFBP-7) with proposed AKI biomarker of cystatin C (CysC) and evaluated whether concentrations of these biomarkers vary with age, body weight, illness severity assessed by pediatric risk of mortality III score, and kidney function assessed by estimated glomerular filtration rate (eGFR). They also ascertained the relationship between these biomarkers and AKI, and assessed if these biomarkers could serve as early independent predictors of AKI in critically ill children. An inverse relation in the serum FGF23 levels and measures of eGFR was seen. In predicting severe AKI in critically ill children, an elevated urinary IGFBP-7 level was independently related to the increased risk of severe AKI diagnosed within the next 5 days after sampling, but not superior to serum or urinary CysC which was contrary to the serum and urinary FGF23 which are not related to AKI in a general and heterogeneous PICU population.

Methods

• In this prospective single center study, authors included 144 critically ill patients admitted to the pediatric intensive care unit (PICU) regardless of diagnosis.
• During the first 24 h after PICU admission, serum and spot urine samples were collected.
• AKI was diagnosed based on the AKI network (AKIN) criteria.

Results

• Findings suggested development of AKI in 21 patients within 120 h of sample collection, including 11 with severe AKI defined as AKIN stages 2 and 3.
• Results demonstrated an independent association of serum FGF23 levels eGFR after adjustment in a multivariate linear analysis (P < 0.001).
• Researchers noted that urinary IGFBP-7 (Adjusted OR=2.94 per 1000 ng/mg increase,P=0.035), serum CysC (Adjusted OR=5.28,P=0.005), and urinary CysC (Adjusted OR=1.13 per 1000 ng/mg increase,P=0.022) remained significantly related to severe AKI after adjustment for body weight and illness severity, respectively.
• As per data, predictive of severe AKI was urinary IGFBP-7 level that achieved the AUC of 0.79 (P=0.001), but was not better than serum (AUC=0.89,P < 0.001) and urinary (AUC=0.88,P < 0.001) CysC in predicting severe AKI.