Normocalcemic hyperparathyroidism: A Collaborative Endocrine Surgery Quality Improvement Program analysis

Background: Normocalcemic primary hyperparathyroidism may be more challenging to cure compared with classical primary hyperparathyroidism. The aim of this study was to utilize a multi-institutional database to better characterize this condition. Methods: The Collaborative Endocrine Surgery Quality Improvement Program database was queried for all patients who underwent parathyroidectomy for sporadic primary hyperparathyroidism. Patient characteristics, operative details, pathology, and outcomes data were compared between patients with normocalcemic primary hyperparathyroidism and those with hypercalcemia. Results: Among 7,569 patients, 9.7% (733) were normocalcemic primary hyperparathyroidism. Mean age at surgery and sex were similar for normocalcemic primary hyperparathyroidism and primary hyperparathyroidism with hypercalcemia. The primary hyperparathyroidism with hypercalcemia cohort had a single parathyroid resected more frequently than the normocalcemic primary hyperparathyroidism group (73.3%% vs 47.5%, P < .05). Patients with normocalcemic primary hyperparathyroidism had a higher rate of subtotal (3.5 gland) resection (10.0% vs 4.7%, P < .05). Pathology reported a higher frequency of multigland hyperplasia in the normocalcemic primary hyperparathyroidism cohort (43.1% vs 21.9%, P <.05). In the normocalcemic primary hyperparathyroidism cohort, 47 patients (6.4%) underwent remedial surgery compared with 307 patients (4.5%) with primary hyperparathyroidism with hypercalcemia (P < .05). The rate of clinical concern for persistent hyperparathyroidism was similar between the 2 groups (P = .09) but not reported in 25% overall. Conclusion: Patients with normocalcemic primary hyperparathyroidism have higher rates of multigland disease and remedial surgery compared with primary hyperparathyroidism with hypercalcemia.