BACKGROUND - 25-OH Vitamin D (VitD) plays a role in serum calcium (Ca) and parathyroid hormone (PTH) homeostasis. VitD insufficiency in patients with primary hyperparathyroidism (HPT) may be associated with greater disease severity and a higher incidence of multi-gland disease and postoperative normocalcemic PTH elevation.
MATERIALS AND METHODS - One hundred ten patients with HPT undergoing parathyroidectomy had preoperative VitD levels as follows: levels were insufficient (< or =20 ng/mL) in 55 patients (group 1) and sufficient (>20 ng/mL) in 55 patients (group 2). All patients had preoperative localizing sestamibi scans and/or ultrasounds and postoperative serum Ca and PTH levels. A focused approach was performed when possible, and intraoperative PTH monitoring (IPM) was used in all patients.
RESULTS - Patients with VitD insufficiency had significantly higher preoperative Ca (11.3 +/- 1.2 versus 10.8 +/- 0.9 mg/dL, P = 0.012) and PTH levels (204 +/- 138 versus 156 +/- 179 pg/mL; P = 0.006) as well as higher bone specific alkaline phosphatase (P = 0.006). Localization studies were similar. IPM levels were significantly higher in group 1 at all time intervals. Both groups were similar in operative time, conversions to bilateral explorations, number of glands removed, and number of frozen sections. The glands in group 1 were larger (1757 versus 524 g; P = 0.005). Postoperative Ca levels, PTH levels, rates of eucalcemia, and rates of eucalcemic PTH elevation were all similar.
CONCLUSION - Patients with HPT and VitD insufficiency may have significantly more severe disease based on preoperative serum Ca and PTH levels, bone markers, and gland size. IPM levels in these patients are higher but can be used to predict postoperative eucalcemia, an outcome which appears be independent of VitD status.