Correlation of Plasma 25-Hydroxyvitamin D Levels With Severity of Primary Hyperparathyroidism and Likelihood of Parathyroid Adenoma Localization on Sestamibi Scan

Objectives: To determine the relationship between preoperative plasma 25-hydroxyvitamin D (25 [OH]D) levels and severity of primary hyperparathyroidism (PHPT) and to explore whether presurgical 25(OH)D levels could predict the likelihood of positive results on technetium Tc 99m sestamibi scintigraphy. Design: Retrospective analysis. Setting: Tertiary university referral center. Patients: A total of 421 consecutive patients underwent preoperative sestamibi scintigraphy and parathyroid exploration. Patients with cholecalciferol (vitamin D) deficiency, defined as plasma levels lower than 25 ng/mL, were compared with patients having no vitamin D deficiency. We explored the relationship between 25 (OH)D levels and intact parathyroid hormone (iPTH) levels, alkaline phosphatase (ALKP) levels, adenoma weight, binary sestamibi scan results, and postoperative serum calcium levels (at I week and 6 months). Main outcome Measures: We hypothesized that severity of hypovitaminosis D would correlate with severity of PHPT and predict the likelihood of a positive finding on sestamibi scan. Results: Concentrations of iPTH and ALKP and parathyroid adenoma weight were significantly higher in patients with lower 25(OH)D levels (P < .01 for all). Patients with hypovitaminosis D had a greater percentage decrease in serum calcium levels I week and 6 months postoperatively (P < .05). Median 25(OH)D levels were lower in patients with positive sestamibi scan results (P < .001). Conclusions: Patients with hypovitaminosis D present with more advanced indices of PHPT. Parathyroid sestamibi scanning is more likely to show positive results for this subset of patients who may then benefit from sestamibi scan-directed surgical intervention.