Fibroblast growth factor-23 (FGF23) is a hormone whose primary function is the regulation of phosphate homeostasis. Increase in FGF23 levels is observed in association with the decline of renal function in both acute and chronic conditions. As such, FGF23 is a biomarker of acute kidney injury, a major health issue whose timely diagnosis is of utmost clinical significance.
Contrast-associated acute kidney injury may occur after diagnostic and interventional procedures using iodinated contrast media, such as coronary angiography. Huang et al. recently proposed the assessment of serum FGF23 levels in the evaluation of risk for contrast-associated acute kidney injury in patients undergoing coronary angiography. They performed a clinical study in 492 patients, showing that serum FGF23 levels are higher in those who develop contrast-associated acute kidney injury compared to those not reporting the adverse effect. The authors observed that doubling of serum FGF23 levels was associated with 103% higher risk for contrast-associated acute kidney injury. Interestingly, higher FGF23 levels were associated with a higher risk of major adverse kidney event. As expected, patients with higher serum FGF23 levels had higher number of comorbidities compared to those with lower levels. Notwithstanding, serum FGF23 showed to be an independent risk factor for developing acute kidney injury after iodine contrast administration.
The results of this study underline how FGF23 should be considered in the assessment of acute kidney injury, particularly in high-risk patients, such as those undergoing coronary angiography. FGF23 is a sensitive and specific biomarker of renal function decline, whose rise may occur much earlier than serum creatinine. Further prospective clinical studies will help in clarifying how FGF23 would be of clinical usefulness, alone or in combination with other sensitive biomarkers, in the diagnosis of contrast-associated acute kidney injury. More data are needed for identifying the correct timing for FGF23 measurement after contrast administration that will allow the early diagnosis of this serious adverse event that strongly impact patients’ clinical management and prognosis.