Vitamin D Repletion in Primary Hyperparathyroidism
Vitamin D Repletion in Primary Hyperparathyroidism
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.
Primary hyperparathyroidism (PHPT) is a common disease in which the parathyroid glands
 produce excessive amounts of parathyroid hormone (PTH), which regulates calcium levels. In
 primary hyperparathyroidism, high levels of PTH remove too much calcium from bones and
 deposit the excess calcium in the blood, which is then filtered into the urine by the
 kidneys. Bone health is threatened by the excess calcium loss which weakens the structure of
 the bones.

 Many patients with primary hyperparathyroidism also have low vitamin D (25OHD) levels which
 is thought to further impair bone health. Recent medical guidelines recommend treating
 patients with primary hyperparathyroidism who have low vitamin D levels with oral vitamin D
 but the optimal vitamin D dose and rate of repletion is unclear. It is, therefore, important
 to determine if replenishing Vitamin D will improve bone health in primary
 hyperparathyroidism, and if so, to assess the impact of the rate of vitamin D repletion.
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.