PTH and chronic kidney disease: The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines define CKD-MBD as a systemic disorder of mineral and bone metabolism due to CKD and manifested by either one or a combination of the following: (1) abnormalities of calcium (Ca), phosphorus (P), parathyroid hormone (PTH), or vitamin D metabolism; (2) abnormalities in bone turnover, mineralization, volume, linear growth, or strength; and (3) vascular or other soft-tissue calcification [1].