Predictive value of age and serum parathormone and vitamin d3 levels for postoperative hypocalcemia after total thyroidectomy for nontoxic multinodular goiter.

HYPOTHESIS Age, postoperative serum parathormone (PTH) level, and preoperative serum 25-hydroxyvitamin D(3) (25-OHD) level predict postoperative hypocalcemia after total thyroidectomy. DESIGN Prospective clinical trial. SETTING Tertiary referral center. PATIENTS One hundred thirty patients with nontoxic multinodular goiter. Patients were divided into 2 groups according to the postoperative serum calcium level. Group 1 (n = 32) consisted of patients with a postoperative serum calcium level of 8 mg/dL or less, and group 2 (n = 98) consisted of patients with a postoperative serum calcium level higher than 8 mg/dL. INTERVENTIONS The preoperative serum 25-OHD level and preoperative and postoperative serum calcium and PTH levels were determined. MAIN OUTCOME MEASURES The number of patients developing hypocalcemia and prediction of postoperative hypocalcemia by the serum 25-OHD and PTH levels. RESULTS Hypocalcemia developed in 32 patients (24.6%) (group 1). The preoperative serum 25-OHD level and postoperative serum calcium and PTH levels in group 1 were significantly lower than in group 2 (P = .001). With logistic regression analysis, factors that were predictive of postoperative hypocalcemia included a preoperative serum 25-OHD level less than 15 ng/mL (P < .001; odds ratio, 558.5), a postoperative serum PTH level less than 10 pg/mL (P = .01; odds ratio, 16.4), and being older than 50 years (P = .01; odds ratio, 4.6). CONCLUSIONS Age, a low preoperative serum 25-OHD level, and a low postoperative serum PTH level are significantly associated with postoperative hypocalcemia. The low preoperative serum 25-OHD level was more significant than the low postoperative serum PTH level in the prediction of postoperative hypocalcemia.