Influencing factors and predictors of short-term normal parathyroid function after thyroidectomy: a case control study

Abstract

Background Postoperative hypoparathyroidism is the main reason for outpatient follow-up and long-term oral calcium and calcitriol treatment. Our study investigated the influencing factors and powerful predictors of postoperative normal parathyroid function. Methods Logistic regression was used to compare the clinicopathological characteristics, surgical details, and serum calcium, magnesium, and phosphorus concentrations of patients. A receiver operating characteristic (ROC) curve was used to analyze the predictors of normal parathyroid hormone (PTH). Results Among the 111 patients with PTH < 10 pg/mL on the first postoperative day, most patients experienced a return to normal PTH (PTH > 15 pg/mL) within 30 days postoperatively. Univariate analysis showed that Pod (postoperative day) 1PTH, Pod3 PTH, Pod7 Ca, Pod7 Mg, and Pod7 P (P < 0.05) were associated with normal parathyroid function on the seventh postoperative day. Multivariate logistic regression analysis revealed the following independent risk factors for normal PTH levels at Pod7 after thyroidectomy: Pod3 PTH (P = 0.038), Pod1 PTH (P = 0.056), Pod7 Mg (P = 0.001), Pod7 P (P = 0.020), and the number of parathyroid glands in situ intraoperatively. The combined sensitivity of serum magnesium concentration and phosphorus concentration to predict normal parathyroid function on the seventh postoperative day was 82.76%, with a sensitivity of 76.83%. Conclusion Serum magnesium concentration, phosphorus concentration and PTH concentrations are important influencing factors and effective predictors of short-term postoperative normal parathyroid function. The surgeon should treat each parathyroid gland as the only one during the operation.