Patients with the highest quartiles of cFGF23 and intact, biologically active protein (iFGF23) had a significantly increased risk of 60-day mortality than those having the lowest quartiles in two cohorts of critical illness involved AKI patients.383 Further study is required to clarify whether aberrant FGF23 contributes to the poor outcomes of AKI. This evidence concerns the gene FGF23 and acute kidney injury.