Normocalcemic primary hyperparathyroidism is not associated with cardiometabolic alterations.

Purpose: Cardiometabolic disorders are non-classical complications of hypercalcemic primary hyperparathyroidism (HC-PHPT), but whether this risk connotes normocalcemic PHPT (NC-PHPT) remains to be elucidated. We investigated cardiometabolic alterations in both forms of PHPT, looking for their association with indices of disease activity.

Methods: Patients with HC-PHPT (n = 17), NC-PHPT (n = 17), and controls (n = 34) matched for age, sex, and BMI were assessed for glucose, lipid, blood pressure alterations, and history of cardiovascular events to perform a case-control study at an ambulatory referral center for Bone Metabolism Diseases.

Results: NC-PHPT, in comparison to controls, showed similar glucose (mean ± SD, 88 ± 11 vs 95 ± 22 mg/dl), total cholesterol (199 ± 25 vs 207 ± 36 mg/dl), and systolic blood pressure levels (SBP, 132 ± 23 vs 132 ± 19 mmHg), together with a comparable frequency of glucose alterations (6% vs 9%), lipid disorders (41% vs 50%) and hypertension (53% vs 59%, p = NS for all comparisons). Conversely, all these abnormalities were more prevalent in HC-PHPT vs controls (p < 0.05). When compared to NC-PHPT, HC-PHPT showed higher glucose (113 ± 31 mg/dl), total cholesterol (238 ± 43 mg/dl), and SBP levels (147 ± 15 mmHg) as well as an increased frequency of glucose (41%) and lipid alterations (77%) and a higher number of cardiovascular events (18% vs 0%, p < 0.05 for all comparisons). Among indices of PHPT activity, calcium levels displayed a significant correlation with glucose (R = 0.46) and SBP values (R = 0.60, p < 0.05).

Conclusion: NC-PHPT is not associated with cardiovascular alterations. The predominant pathogenetic role of hypercalcemia in the development of cardiometabolic disorders could account for the absence of such alterations in NC-PHPT.