Upacicalcet on coronary calcification measured in patients undergoing hemodialysis(UPCOMING)

INTERVENTION: Early intervention group Upacicalcet + low dose of active vitamin D (Active vitamin D may be increased, decreased, discontinued, or not administered within the doses specified in the study) Conventional therapy group Administration of active vitamin D (The dosage of active vitamin D may be increased freely within the limits of the package insert) CONDITION: Secondary hyperparathyroidism (SHPT) PRIMARY OUTCOME: The amount of change in log‐transformed CACS (volume) from baseline (observation period) to 52 weeks (12 months) after study treatment. SECONDARY OUTCOME: (1) CACS; The amount of change in log‐transformed CACS (Agatston score) from baseline (observation period) to 52 weeks (12 months) after study treatment.; The proportion of patients with increasing greater than 15% for CACS (volume and Agatston score) (comparison of observation period vs. after 52 weeks from starting of study treatment [12 months]).; (2) Total deaths during the study treatment period (all deaths regardless of cause).; (3) Incidence of major adverse cardiovascular events during the study treatment period.; Major adverse cardiovascular events are defined as cardiovascular death, non‐fatal myocardial infarction, unstable angina, heart failure, stroke, and other cardiovascular events requiring hospitalization.; (4) Blood biochemical tests; Phosphorus (P), corrected calcium (Ca), corrected calcium‐phosphorus (Ca * P) product, intact FGF23 and intact PTH.; The rate of change and amount of change between baseline (observation period) and at each time point during the study treatment period of above parameters.; (5) Progression of aortic stenosis severity during the study treatment period. INCLUSION CRITERIA: (1) Patients who have obtained written consent of their own free will based on full understanding after receiving sufficient explanation prior to participation in this study. (2) Patients who are at least 18 years old at the time of obtaining consent to participate in this study. (3) At the time of the informed consent, patients must be scheduled to be on dialysis or have been on dialysis for less than 60 months. (4) Patients with intact PTH concentration > 240 pg/mL during the observation period. (5) Patients with serum corrected calcium concentration > 8.4 mg/dL during the observation period. (6) Patients with CACS >= 30 during the observation period. (7) Patients who have not received any calcimimetics within 4 weeks prior to enrollment. (8) Patients who have not changed the dosage or started or stopped administration of active vitamin D within 4 weeks prior to enrollment. Patients who have received an active vitamin D preparation with