Pattern of calcium and parathyroid hormone normalization at 12-months follow-up after parathyroid operation

At 12 months after a parathyroid operation, we expect cured patients to have biochemical profiles similar to those of healthy individuals. The aim of the current study was to compare the biochemical characteristics patients at 12 months after parathyroidectomy for primary sporadic hyperparathyroidism with those of healthy controls.

A total of 547 patients who underwent parathyroid neck operation for primary sporadic hyperparathyroidism from 2000-2014 were analyzed. A control group consisted of 74 healthy subjects. Calcium and parathyroid hormone were collected perioperatively. Graphic plots of the relationship between calcium versus parathyroid hormone (95% confidence intervals) were used to compare the biochemical profiles of patients after parathyroid operation and controls.

Preoperatively, patients with primary sporadic hyperparathyroidism had a calcium level of 10.9 ± 0.5 mg/dL and parathyroid hormone level of 124.4 ± 68.5 pg/dL vs controls' values of 9.2 ± 0.3 mg/dL and 34.4 ± 13.4 pg/dL, respectively. Before operation, all primary sporadic hyperparathyroidism patients had calcium versus parathyroid hormone values outside the normal zone. At 12 months after operation, 335 (69%) patients showed normalization of the chemical profile; 13 (2.7%) had absolute elevation of calcium and parathyroid hormone, reflecting persistent disease; 2 (0.4%) patients had hypoparathyroidism after subtotal parathyroidectomy; and 149 (31%) had calcium and parathyroid hormone values outside the normal zone, not fitting into the above categories. There were no marked differences between patients with simple adenoma those with multiple-gland disease.

Longer follow-up might be needed for patients after parathyroid operation to confirm stabilization of biochemical profiles.