The Impact of Age, Vitamin D(3) Level, and Incidental Parathyroidectomy on Postoperative Hypocalcemia After Total or Near Total Thyroidectomy

Background: Hypocalcemia caused by transient or definitive hypoparathyroidism is the most frequent complication after thyroidectomy. We aimed to compare the impact of incidental parathyroidectomy and serum vitamin D(3) level on postoperative hypocalcemia after total thyroidectomy (TT) or near total thyroidectomy (NTT).

Patients: Two hundred consecutive patients with nontoxic multinodular goiter treated by TT and NTT were included prospectively in the present study. Group 1 (n = 49) consisted of patients with a postoperative serum calcium level < or =8 mg/dL, and group 2 (n = 151) had a postoperative serum calcium level greater than 8 mg/dL. Patients were evaluated according to age, preoperative serum 25-hydroxy vitamin D (25-OHD) levels, postoperative serum calcium levels, incidental parathyroidectomy, and the type of thyroidectomy.

Results: Patients in group 1 (n = 49) were hypocalcemic, whereas patients in group 2 (n = 151) were normocalcemic. Preoperative serum 25-OHD levels in group 1 were significantly lower than in group 2 (P < .001). The incidence of hypoparathyroidism was significantly higher following TT (13.5%) than following NTT (2.5%) (P < .05). The risk for postoperative hypocalcemia was increased 25-fold for patients older than 50 years, 28-fold for patients with a preoperative serum 25-OHD level less than 15 ng/mL, and 71-fold for patients who underwent TT. Incidental parathyroidectomy did not have an impact on postoperative hypocalcemia. The highest risk of postoperative hypocalcemia was found in the patients with all of the above variables.

Conclusions: Age, preoperative low serum 25-OHD, and TT are significantly associated with postoperative hypocalcemia. Patients with advanced age and low preoperative serum 25-OHD levels should be placed on calcium or vitamin D supplementation after TT to avoid postoperative hypocalcemia and decrease hospital stay.