Original Article Fibroblast growth factor 23 and soluble klotho in children with chronic kidney disease

Background. Fibroblast growth factor 23 (FGF23), a bone-derived phosphaturic hormone, is elevated in chronic kidney disease (CKD). There are scarce data on the levels of its essential co-receptor klotho, and longi-tudinal changes in FGF23 levels are also unknown. Methods. We examined FGF23 and soluble klotho (s-klotho) levels over 1 year in 154 children with CKD Stages 1–5 (CKD1–5), were on dialysis or who have re-ceived a transplantation. Results. In children with CKD1–5 and who were receiv-ing dialysis, FGF23 correlated inversely with the esti-mated glomerular filtration rate (eGFR) (P < 0.001), whereas a decrease in s-klotho was observed with a lower eGFR (P = 0.01). There was no correlation betwee