PTH and chronic kidney disease: Nutritional vitamin D supplements are not specifically indicated for SHPT in non-dialysis CKD, and while many studies have explored their therapeutic potential, the evidence supporting a positive impact on serum 25(OH)D and PTH in non-dialysis CKD, has been largely based on data extrapolated from observational studies in patients with CKD stage G3–G5D and renal transplant recipients with mixed results [44].