The predictive factors for postoperative hypoparathyroidism and its severity on the first postoperative day after papillary thyroid carcinoma surgery

Abstract

Purpose The purpose of the study was to investigate the predictive factors for hypoparathyroidism and its severity on the first postoperative day (POD1) after total thyroidectomy (TT) with or without central neck dissection (CND) in patients with papillary thyroid carcinoma (PTC). Methods From February 2014 to February 2019, 2550 PTC patients were admitted to our department. PTC patients who underwent TT were enrolled in this study. A parathyroid hormone (PTH) level lower than 15 pg/mL on POD1 was defined as hypoparathyroidism, and the severity of hypoparathyroidism was classified into three categories according to the level of PTH on POD1: mild hypoparathyroidism (10 pg/mL ≤ PTH < 15 pg/mL), moderate hypoparathyroidism (5 g/mL ≤ PTH < 10 pg/ mL), and severe hypoparathyroidism (PTH < 5 pg/mL). Multiple clinical, pathological and surgical parameters of these two different groups were compared and analyzed to demonstrate the possible causes of hypoparathyroidism. Furthermore, patients who developed postoperative hypoparathyroidism were also included in a subgroup analysis according to the severity of their hypoparathyroidism. The underlying factors affecting different severities of hypoparathyroidism were also illustrated with univariate and multivariate analyses. Results Ultimately, 690 patients who underwent TT were enrolled in this retrospective study. Through the univariate analysis, different surgeons (P < 0.001), extent of CND (P = 0.009), prophylactic calcium supplementation (PCS) (P < 0.001), preoperative (pre-op) PTH level (P < 0.001), and pre-op phosphorus concentration (P = 0.022) were found to be significantly correlated with postoperative hypoparathyroidism. According to the multivariate analysis, PCS was the only independent high-risk factor for hypoparathyroidism. In the univariate analysis of patient subgroups with different severities of hypoparathyroidism, we demonstrated that the tumor T stage (P = 0.021) and pre-op PTH level (P < 0.001) were associated with the severity of hypoparathyroidism. Furthermore, after the multivariate analysis, hypertension (P < 0.001) and pre-op PTH (P < 0.001) were the two independent predictive factors for the severity of hypoparathyroidism after surgery. Conclusions Postoperative PCS could increase the risk for PTC patients developing hypoparathyroidism after thyroid surgery. Patients with a history of hypertension and a relatively high pre-op PTH level may not develop severe hypoparathyroidism after TT with CND.

Vitamin D Insufficiency Predicts Susceptibility of Parathyroid Hormone Reduction after Total Thyroidectomy in Thyroid Cancer Patients

“…Both retrospective studies found bilateral CND was associated with a significantly increased rate of transient hypoparathyroidism. However, another retrospective study of 690 TT patients found a different result after controlling other confounding factors [ 17 ]. Huang et al [ 17 ] showed the extent of CND was not independently associated with postoperative hypoparathyroidism after adjusting for other confounding factors such as surgeon, intraoperative carbon nanoparticle injection, and preoperative PTH.…”

“…However, another retrospective study of 690 TT patients found a different result after controlling other confounding factors [ 17 ]. Huang et al [ 17 ] showed the extent of CND was not independently associated with postoperative hypoparathyroidism after adjusting for other confounding factors such as surgeon, intraoperative carbon nanoparticle injection, and preoperative PTH. In our study, neither bilateral CND nor LND was statistically associated with postoperative hypoparathyroidism.…”

“…Preoperative PTH was scarcely discussed in previous studies about its effect on postoperative hypoparathyroidism or hypocalcemia. In a few studies that did discuss its role, preoperative PTH had a positive correlation with postoperative PTH [ 17 , 29 ]. Huang et al [ 17 ] enrolled 690 PTC patients who underwent TT with or without CND to investigate the predictive factors for postoperative hypoparathyroidism (PTH < 15 pg/mL) on the first postoperative day.…”

“…In a few studies that did discuss its role, preoperative PTH had a positive correlation with postoperative PTH [ 17 , 29 ]. Huang et al [ 17 ] enrolled 690 PTC patients who underwent TT with or without CND to investigate the predictive factors for postoperative hypoparathyroidism (PTH < 15 pg/mL) on the first postoperative day. The preoperative PTH was significantly lower in the hypoparathyroidism group (42.94 vs. 48.5, p < 0.001).…”

“…The preoperative PTH was significantly lower in the hypoparathyroidism group (42.94 vs. 48.5, p < 0.001). To further discuss its effect on the severity of postoperative hypoparathyroidism, Huang et al [ 17 ] classified all patients in the hypoparathyroidism group into three subgroups: mild hypoparathyroidism (10 pg/mL ≤ PTH < 15 pg/mL), moderate (5 pg/mL ≤ PTH < 10 pg/mL), and severe (PTH < 5 pg/mL). The median preoperative PTH levels of these three subgroups were 45.1, 44.3, and 36.5 pg/mL, respectively ( p < 0.001).…”