Vitamin D Does Not Affect Intraoperative Parathyroid Hormone Kinetics: A Mixed Linear Model Analysis

Area of Science:

• Endocrinology
• Surgical Oncology
• Biochemistry

Background:

• Intraoperative parathyroid hormone (ioPTH) monitoring is crucial for confirming complete resection during parathyroidectomy for primary hyperparathyroidism (pHPT).
• While an inverse relationship exists between vitamin D and parathyroid hormone (PTH), prior research indicated that 25-hydroxyvitamin D (25OHD) levels do not influence achieving the Miami criterion.
• This study investigates the specific impact of preoperative 25OHD levels on ioPTH kinetics.

Purpose of the Study:

• To determine if preoperative 25-hydroxyvitamin D (25OHD) levels affect intraoperative parathyroid hormone (ioPTH) kinetics in patients undergoing parathyroidectomy for primary hyperparathyroidism (pHPT).
• To assess the clinical utility of ioPTH monitoring across different vitamin D statuses.

Main Methods:

• A retrospective case-control study involving 630 patients undergoing parathyroidectomy for pHPT.
• Patients were stratified into three groups based on preoperative 25OHD levels: deficient (≤20 ng/mL), insufficient (21-30 ng/mL), and sufficient (>30 ng/mL).
• ioPTH kinetic curves were analyzed using a log-transformed mixed linear model, with significance set at P < 0.05.

Main Results:

• A significant difference in baseline ioPTH was observed between the vitamin D groups (P < 0.001), but no significant differences were found at subsequent time points.
• Analysis using a mixed linear model, treating vitamin D status as both a continuous and categorical variable, revealed no significant effect on ioPTH kinetics.
• The Miami criterion's achievement was not significantly influenced by preoperative 25OHD levels.

Conclusions:

• Preoperative 25-hydroxyvitamin D (25OHD) levels do not significantly alter intraoperative parathyroid hormone (ioPTH) kinetics following parathyroidectomy for primary hyperparathyroidism.
• ioPTH assays can be reliably interpreted irrespective of a patient's preoperative vitamin D status.
• This supports the uniform application of ioPTH monitoring in parathyroidectomy for pHPT.