The MBD-5D is a prospective observational study with a case-cohort and a cohort design. Eligible patients are receiving hemodialysis and have secondary hyperparathyroidism. The study's three goals are (1) to record the patients' characteristics, and variation in the patterns of their treatment; (2) to analyze factors associated with variation in those medical practice patterns; and (3) to identify practice patterns and other factors that affect hospitalization, mortality, and other patient-level outcomes.

The MBD-5D is a 3-year prospective observational study with a case-cohort and a cohort design. Eligible patients comprise all patients who are receiving hemodialysis at the participating facilities, and who also have secondary hyperparathyroidism(2HPT). The study has 3 goals: to record the characteristics of those patients and variation in the patterns of their treatment; to analyze factors associated with variation in those medical practice patterns; and to identify the practice patterns and other factors that affect hospitalization, mortality, and other patient-level outcomes. In the case-cohort study, the outcomes are relatively infrequent events (all-cause and cardiovascular mortality). The cohort study includes a randomly selected sample of 40% of all study participants; and the outcomes are hospitalization, parathyroid interventions, bone fracture, MBD management status, etc. Explanatory variables comprise medications and other factors likely to be associated with outcomes of dialysis and of 2HPT, and facility-level practice patterns.

Inclusion Criteria:

• patients receiving hemodialysis
• patients whose intact PTH concentration is at least 180 pg/mL (106 pg/mL for whole PTH) OR patients who are receiving intravenous active vitamin D sterols or oral active vitamin D sterols (falecalcitriol)

Exclusion Criteria:

• patients have been undergoing hemodialysis for less than 3 months

patients who are undergoing hemodialysis and who also have secondary hyperparathyroidism(2HPT)