FGF23 and chronic kidney disease: In CKD patients, the number of carotid plaques did not correlate to the serum levels of sKlotho (r = 0.016; p = 0.921) (Supplemental Figure S2c), phosphorus (r = 0.157; p = 0.314), or FGF23 (r = 0.172; p = 0.271), and only a trend was found with serum PTH (r = 0.295; p = 0.055).