Vitamin D Repletion in Primary Hyperparathyroidism
Condition: Primary Hyperparathyroidism; Vitamin D Deficiency
MeSH terms: Vitamin D Deficiency; Hyperparathyroidism; Hyperparathyroidism, Primary
Intervention: 10,000 IU Vitamin D3; Placebo; Vitamin D
Intervention description: Month 1: 20,000 IU vitamin D3 once a week
Months 2-6: 10,000 IU vitamin D3 once a week; Month 1: Placebo once a week
Months 2-6: Placebo once a week; Daily multivitamin with 400 IU vitamin D.
Intervention MeSH terms: Vitamin D; Ergocalciferols; Cholecalciferol; Vitamins
Phase: Phase 4
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Active arm:
Month 1: 20,000 IU vitamin D3 once a week, plus daily multivitamin with 400 IU vitamin D.
Months 2-6: 10,000 IU vitamin D3 once a week, plus daily multivitamin with 400 IU vitamin D.
Placebo arm:
Month 1: Placebo once a week plus daily multivitamin with 400 IU vitamin D.
Months 2-6: Placebo every week plus daily multivitamin with 400 IU vitamin D.
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Masking description: Patient, investigator and study team will be blinded to study arm ramdomization.
Enrollment: 9.0
Sex: All
Minimum age: 18 Years
Healthy volunteers: No
Keywords: Endocrinology; Metabolic Bone Disease; Primary Hyperparathyroidism; PHPT; Vitamin D Deficiency; Bone Mineral Density; Hyper-calcemia

Summary:

      This study will look at the effect of 2 treatment regimens that contain vitamin D in a
      six-month treatment trial of patients with PHPT who are vitamin D deficient. Patients will be
      assigned randomly to one of 2 regimens, and will be followed with tests of their blood, urine
      and bones. This study should provide important information on the effect of vitamin D therapy
      in patients with PHPT. In addition, data from this study will guide physicians as to how best
      to treat their patients who have PHPT and vitamin D deficiency.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Diagnosed PHPT, defined by an elevated serum calcium level (we will not study
             normocalcemic PHPT) with elevated or inappropriately normal PTH levels.

          -  Vitamin D3 less than 30 ng/ml

        Exclusion Criteria:

          -  Patients with familial hyperparathyroid syndromes

          -  Current or past use of the following medications: bisphosphonate within past 2 years,
             use of lithium or thiazide diuretics, current use of cinacalcet, use of aluminum
             containing medications, cimetidine, colestipol, or orlistat

          -  Malignancy, except cured basal or squamous cell skin carcinoma or other cured cancers
             that are at least five years free from recurrence

          -  History or current diagnosis of certain medical diseases (including sarcoidosis,
             active infectious granulomatous disease, HIV/AIDS, chronic kidney disease (serum
             creatinine > 1.5 mg/dL), liver disease; GI diseases known to affect calcium
             metabolism; secondary hyperparathyroidism);

          -  We will also exclude patients with calcium above 11.5 mg/dL, urine calcium above 350
             mg/day, and active nephrolithiasis because vitamin D repletion could potentially
             exacerbate hypercalcemia or hypercalciuria

          -  Other exclusions include protected individuals (institutionalized), prisoners, and any
             other prospective participant who might not be able to give voluntary informed
             consent.