PTH and chronic kidney disease: In the CKD and CKD-T groups, log FGF23 was noted to have changed significantly at a GFR of 45 and 38 ml/min/1.73 m2, i-PTH at a GFR of 33 and 40 ml/min/1.73 m2, phosphate at a GFR of 36 and 21 ml/min/1.73 m2 and albumin-adjusted calcium at a GFR of 13 and 26 ml/min/1.73m2, respectively.