FGF23 and secondary hyperparathyroidism: CKD progression also correlates with the onset of anaemia; metabolic acidosis, which predisposes individuals to hyperkalaemia; the retention of uremic toxins, including phosphorus; and hyperphosphatemia, which contributes to high blood levels of Fibroblast growth factor 23 (FGF23), low levels of 1.25-dihydroxy vitamin D3, and secondary hyperparathyroidism, which leads to mineral bone disease (osteoporosis and a high risk of bone fractures), vascular calcifications, and cardiovascular events that cause a dramatic increase in healthcare costs [6,7,8].