Normocalcemic Hyperparathyroidism: Bridging the Gap in Parathyroid Research

Abstract

Introduction: Previous studies from single-institution cohorts have shown that patients with normocalcemic primary hyperparathyroidism (ncPHPT) are just as symptomatic as patients with classic PHPT. There is currently no large-scale database analysis of ncPHPT, so with the TriNetX database, a large international database, trends on ncPHPT can be studied over a large cohort of patients. The aim of this project is to characterize the diagnostic and treatment paradigm for ncPHPT in the TriNetX database.

Materials and methods: We conducted a retrospective cohort study of patients with ncPHPT using the TriNetX Research Network, which includes patients from 52 healthcare organizations from 2007 to 2023. ncPHPT was defined as having parathyroid hormone (PTH) ≥66pg/mL and calcium between 8.4 and 10.4 mg/dL. We excluded patients with secondary, tertiary, and classic hyperparathyroidism and other hypercalcemia inducing factors.

Results: We found 5092 patients with ncPHPT; 78.2% were female, average age was 69 ± 13 y, and 78.9% were White. The average serum calcium was 9.7 ± 0.5 mg/dL, while the average serum PTH level was 97 ± 77.5 pg/mL. Of these, 2036 (40%) underwent a parathyroidectomy. Presurgery, calcium averaged 9.9 ± 0.1 mg/dL and PTH averaged 96 ± 152 pg/mL. Postsurgery, calcium averaged 9.3 ± 0.6 mg/dL, while PTH averaged 52 ± 33pg/mL.

Conclusions: In this large multi-institutional cohort, the minority of patients with ncPHPT underwent a parathyroidectomy. Education about the benefits of surgery for these patients to these providers is needed.

Keywords: Endocrine surgery; Hyperparathyroidism; Normocalcemic hyperparathyroidism; Parathyroid surgery; Parathyroidectomy; Primary hyperparathyroidism.