Author(s): Norman J, Goodman A, Politz D
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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.
This article was published in Endocr Pract
and referenced in Journal of Surgery