The impact of vitamin D status and tumor size on the intraoperative parathyroid hormone dynamics in patients with symptomatic primary hyperparathyroidism.

ABSTRACT

PURPOSE: The intraoperative parathyroid hormone (IOPTH) monitoring is a useful adjunct for predicting whether a cure has been obtained during parathyroidectomy. We studied the influence of vitamin D status and parathyroid tumor weight on the IOPTH dynamics for predicting a cure in patients with symptomatic primary hyperparathyroidism. METHODS: Fifty-nine primary hyperparathyroidism patients with a single adenoma underwent curative surgery. Patients were grouped according to their serum 25-hydroxy vitamin D levels (deficient, insufficient and sufficient) and tumor weights (small, large and giant). The IOPTH results in patient groups were compared, and the percentage of the IOPTH decrease was examined for a correlation with the serum 25-hydroxy vitamin D level and tumor weight. RESULTS: The sensitivity, specificity and overall accuracy of IOPTH in predicting a cure of hyperparathyroidism were 94.8, 100 and 93.2%, respectively. The percentage decrease in the IOTPH was significantly higher in the vitamin D deficient, compared to the vitamin D sufficient patients (p = 0.012); and in the patients with larger tumors, compared to those with smaller parathyroid tumors (p = 0.02). A statistically significant correlation was found between the percentage decrease in the IOPTH at 10 min post-tumor excision and the serum 25-hydroxy vitamin D level (p = 0.037), but not with the tumor weight (p = 0.208). CONCLUSIONS: The IOPTH can accurately predict a cure in patients with severe primary hyperparathyroidism. The percentage of decrease in the IOPTH is steeper in patients with lower serum 25-hydroxy vitamin D levels and larger parathyroid tumors.