PTH and chronic kidney disease: In a study of patients with non-dialysis CKD (n = 95), high-dose (8000 IU/day) cholecalciferol was shown to increase calcitriol [1,25(OH)2D] levels, and although further increases in PTH were not seen in the cholecalciferol group, which may have to be regarded as a “partial response”, PTH levels were not reduced from baseline and the proportion of patients achieving a 30% decrease in PTH levels did not differ from placebo [16].