PTH and chronic kidney disease: In subgroup analyses, for those in the CKD Stage 3 subgroup PTH did not change in either treatment arm; for those in the CKD Stage 4 subgroup, the mean PTH changed from 13  ±  7 to 12  ±  6 pmol/L in the treatment group, and from 16  ±  11 to 19  ±  12 pmol/L in the placebo group.