180: Outcomes of parathyroidectomy in patients with or without 25 hydroxy vitamin D insufficiency

Abstract

Background: 25-OH Vitamin D (VitD) plays a role in serum calcium (Ca) and parathyroid hormone (PTH) homeostasis. We hypothesized that VitD insufficiency in patients with primary hyperparathayroidism (HPT) may be associated with greater disease severity and higher incidence of multiglandular disease and postoperative normocalcemic PTH elevation. Methods: 110 patients treated surgically for HPT had preoperative VitD levels. Fifty-five patients in Group 1 had levels ≤20 ng/ml (insufficient), and 55 patients in Group 2 had VitD levels >20 ng/ml (sufficient). All patients had pre and postoperative serum Ca & PTH levels and preoperative localization using sestamibi and/or ultrasound. A focused approach was performed when possible, and intraoperative PTH monitoring (IPM) was utilized in all patients. Analysis was performed using two sample t-test, Wilcoxon rank sum, chi square, and Fisher exact test with p< 0.05 indicating significance. Results: VitD insufficient patients had significantly higher preoperative serum Ca (11.3 ± 1.2 vs. 10.8 ± 0.9 mg/dl, p=0.012) and PTH levels (204 ± 138 vs. 156 ± 179 pg/ml; p=0.006) as well as more advanced bone disease (p<0.001). Results from localization studies were similar between groups. Intraoperative PTH levels were significantly higher in Group 1 at baseline (p=0.02), 5 minutes (p=0.01), and 10 minutes post gland excision (p=0.009). Both groups were similar in operative time, conversions to bilateral explorations, number of glands removed, number of gland biopsies, and frozen sections. The glands in Group 1 were larger (1757 ± 3968 vs. 524 ± 244 gm; p=0.005). The incidence of cure (98% vs. 100%), and normocalcemic PTH elevation were similar. Postoperative serum Ca (9.4 ± 0.9 vs. 9.4 ± 0.5 mg/dl) and PTH (69 ± 65 vs. 51 ± 35 pg/ml; p=0.382) were similar. Postoperative VitD levels were not affected by parathyroidectomy. Conclusion: Patients with HPT and VitD insufficiency have significantly more severe disease based on preoperative serum Ca and PTH levels, bone markers, and parathyroid gland size. Intraoperative PTH levels in VitD insufficient patients are typically higher but IPM can still be used to accurately predict cure. Parathyroidectomy cure rates are similar regardless of preoperative VitD status. Patients with HPT and VitD insufficiency may benefit from oral VitD supplementation after parathyroidectomy.