PTH and chronic kidney disease: In sum, across populations and formulations, hard-outcome signals remain largely neutral: VITAL, D-Health, and WHI did not show clear benefits; in non-dialysis CKD, VDRAs lowered PTH without improving LV structure/function or clinical outcomes and posed hypercalcemia concerns; in dialysis, alfacalcidol was neutral for CV and mortality, while nutritional vitamin D corrected deficiency and improved labs but lacked definitive hard-outcome benefits.