Another study was made in patients with CKD stages 3 and 4 and with vitamin D values over 23 ng/mL and a stable GFR, they managed an adequate response to cholecalciferol in a course of 5 years follow up (considered for the suppression of PTH levels and to obtain vitamin D levels between 40 and 60 ng/mL) 43. Here, PTH is linked to chronic kidney disease.