Objective:To investigate the effect of 25 hydroxyvitamin D [25 (OH) D] on postoperative parathyroid function in patients with papillary thyroid carcinoma (PTC) .Methods:426 patients who diagnosed as PTC and underwent at least total thyroidectomy plus central lymph node dissection (including lateral lymph node dissection) in Center of Thyroid and Parathyroid Surgery of West China Hospital, Sichuan University, from Jun. 2017 to Sep. 2019 were retrospectively analyzed. Among them, 313 were women and 113 were men, they were divided into vitamin D deficient (VDD) group ( n=297) and normal group ( n=129) according to preoperative 25 (OH) D levels ≤ 20ng/ml and > 20ng/ml. SPSS 23.0 statistical software was used for data processing. Pearson χ2 test or Fisher exact test were used to compare the incidence of clinical hypoparathyroidism, biochemical temporary and biochemical permanent hypoparathyroidism between the two groups. Univariate and multivariate logistic regression analysis were used to analyze the related factors of postoperative hypoparathyroidism between the two groups. Results:Preoperative 25 (OH) D level was significantly correlated with postoperative biochemical temporary hypoparathyroidism ( P=0.04, OR=1.11) . Compared with patients with adequate preoperative vitamin D, preoperative vitamin D deficiency increased the risk of biochemical transient hypoparathyroidism by 6.67 times ( P=0.03;OR=6.67) . There was no significant correlation between preoperative vitamin D deficiency and early postoperative clinical hypoparathyroidism (2.7% vs 3.9%, P=0.55) . Conclusion:Correction of vitamin D deficiency before operation may reduce the incidence of postoperative temporary hypoparathyroidism caused by 25 (OH) D deficiency.

Objective:To investigate the value of the decrease rate of parathyroid hormone (PTH) in predicting permanent hypoparathyroidism (PHP) in one month after operation of papillary thyroid carcinoma (PTC) .Methods:The clinical data of 322 patients with PTC who underwent at least total thyroidectomy and unilateral central lymph node dissection in the Thyroid Surgery Center of West China Hospital of Sichuan University from Jan. 2013 to Jun. 2018 were retrospectively analyzed. There were 257 women and 65 men. According to the time when PTH returned to normal, they were divided into 307 cases in the temporary hypoparathyroidism (THP) group and 15 cases in the PHP group. The decrease rate of PTH and the incidence of hypoparathyroidism in one month after operation were counted, the clinical characteristics and operation information were observed, and the risk factors of PHP were analyzed. SPSS 23.0 statistical software was used for data processing. χ 2 test and t test were used for comparison between THP and PHP. The related factors were analyzed by multivariate logistic regression. Results:307 cases of THP and 15 cases of PHP were included. Multivariate logistic analysis showed that age ≥ 55 years old ( OR, 35.193; 95% CI, 2.936 - 421.870; P=0.005) and PTH before operation closer to normal lower limit ( OR, 2.349; 95% CI, 1.161 - 4.755; P = 0.018) were independent risk factors for PHP. Patients with PHP had a higher rate of PTH decline in 1 month after operation ( OR, 373.439; 95% CI, 26.568 - 5248.983; P=0.000) . The ROC curve showed that the sensitivity and specificity of predicting PHP were 86.7% and 94.8% respectively. Conclusions:The age of patients with PTC ≥ 55 years old and PTH before operation closer to normal lower limit are independent risk factors for the occurrence of PHP. The decline rate of PTH in one month after operation which more than 73.2% can predict PHP.