Calcium, parathyroid hormone, and vitamin D in patients with primary hyperparathyroidism: normograms developed from 10,000 cases

Endocr Pract. May-Jun 2011;17(3):384-94. doi: 10.4158/EP09346.OR.

Abstract

Objective: To better define the typical and atypical biochemical profiles of patients with surgically proven primary hyperparathyroidism.

Methods: In this single-center, prospectively conducted study of consecutive patients with surgically proven primary hyperparathyroidism over a 7-year period, we analyzed serum calcium, parathyroid hormone, and 25-hydroxyvitamin D concentrations.

Results: A total of 10 000 patients were included, and more than 210 000 calcium, parathyroid hormone, and 25-hydroxyvitamin D values were evaluated. Both calcium and parathyroid hormone levels demonstrated a Gaussian distribution with the average calcium concentration being 10.9 ± 0.6 mg/dL and the average parathyroid hormone concentration being 105.8 ± 48 pg/mL. The average highest calcium and parathyroid hormone concentrations were 11.4 ± 0.7 mg/dL and 115.3 ± 50 pg/mL, respectively. At least 1 calcium value of 11.0 mg/dL was seen in 87% of patients, but only 21% had 1 or more calcium value above 11.5 mg/dL. Only 7% had a single serum calcium level reaching 12.0 mg/dL. Normocalcemic hyperparathyroidism was seen in just under 3% of patients who had identical findings at surgery. An average parathyroid hormone concentration less than 65 pg/mL was seen in 16%, with 10% of patients who had no high parathyroid hormone values. The average 25-hydroxyvitamin D concentration was 22.4 ± 9 ng/mL, with levels decreasing as calcium levels increased (P<.001); 36% had 25-hydroxyvitamin D levels below 20 ng/mL.

Conclusions: Patients with PHPT present with a number of distinct biochemical profiles, but as a group, they present with a near-normal Gaussian distribution of both calcium and parathyroid hormone levels. Either serum calcium or parathyroid hormone remained normal in 13% of patients, yet the findings at surgery are similar to those of patients with elevated calcium or parathyroid hormone. Low 25-hydroxyvitamin D is an expected finding in patients with PHPT, decreasing as serum calcium levels increase.

Publication types

  • Evaluation Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Calcium / blood*
  • Case-Control Studies
  • Female
  • Humans
  • Hyperparathyroidism, Primary / blood*
  • Male
  • Middle Aged
  • Nomograms*
  • Parathyroid Hormone / blood*
  • Vitamin D / blood*
  • Young Adult

Substances

  • Parathyroid Hormone
  • Vitamin D
  • Calcium