Garg Surabhi, Mishra Anand K, Singh Kul R, Enny Loreno E, Ramakant Pooja
Department of Endocrine Surgery, King George's Medical University, Shah Meena Road, Lucknow, Uttar Pradesh, India.
Indian J Endocrinol Metab. 2021 Jul-Aug;25(4):332-336. doi: 10.4103/ijem.IJEM_797_20. Epub 2021 Dec 15.
Post thyroidectomy hypocalcemia is a common complication. Post thyroidectomy PTH estimation at varying cut offs and time have been used to predict hypocalcemia and aid in early and safe discharge. Single post thyroidectomy PTH values may be spuriously normal or high in a patient that subsequently develops unanticipated low calcium levels. This study aimed to evaluate the percentage change in preoperative and postoperative PTH (Gradient) in predicting post thyroidectomy hypocalcemia.
Forty-one patients of thyroidectomy had PTH preoperatively, postoperatively one-hour (PTH0) and day 1 (PTH1). PTH gradient was calculated as percentage change in postoperative PTH to preoperative (PTHG0, PTHG1). Hypocalcemia was categorized into mild or severe based on corrected calcium values and presence of clinical signs and/or symptoms of hypocalcemia.
Ten (24.3%) and 11 (26.8%) patients had mild and severe hypocalcemia, respectively. PTHG0 and PTHG1 were significantly associated with risk for hypocalcemia (-0.006 vs -0.002). Higher PTH0 and PTH1 gradients were significantly associated with risk of hypocalcemia (PTH0 gradient OR-0.006, 95% CI 0.00-0.175, -0.006; PTH1 gradient OR- 0.008, 95% CI 0.00-0.166, -0.002). PTH0 gradient was the best predictor of hypocalcemia (AUC 0.855, SE-0.065, 95% CI0.710 to 0.945, value <0.001) and PTH1 value was a better predictor of severe/clinical hypocalcemia (AUC 0.844, SE-0.072, 95% CI 0.697 to 0.938, - value-0.001). Based on ROC, cutoffs of PTH0 gradient and PTH1 gradient for predicting hypocalcemia and severe/clinical hypocalcemia were taken as 60% and 75%, respectively (sensitivity 70%, specificity 90.5% for hypocalcemia; sensitivity 65%, specificity 90.9% for severe hypocalcemia).
PTH gradient may be a better predictor of hypocalcemia and PTH1 gradient of >75% correlates with high risk of severe/clinical post thyroidectomy hypocalcemia.
甲状腺切除术后低钙血症是一种常见并发症。通过在不同的临界值和时间点评估甲状腺切除术后的甲状旁腺激素（PTH）来预测低钙血症，并有助于早期安全出院。在随后出现意外低钙水平的患者中，单次甲状腺切除术后PTH值可能会假性正常或偏高。本研究旨在评估术前和术后PTH的百分比变化（梯度）在预测甲状腺切除术后低钙血症中的作用。
41例接受甲状腺切除术的患者在术前、术后1小时（PTH0）和术后第1天（PTH1）检测PTH。PTH梯度计算为术后PTH相对于术前的百分比变化（PTHG0，PTHG1）。根据校正后的钙值以及低钙血症的临床体征和/或症状，将低钙血症分为轻度或重度。
分别有10例（24.3%）和11例（26.8%）患者发生轻度和重度低钙血症。PTHG0和PTHG1与低钙血症风险显著相关（-0.006对-0.002）。较高的PTH0和PTH1梯度与低钙血症风险显著相关（PTH0梯度比值比-0.006，95%可信区间0.00-0.175，-0.006；PTH1梯度比值比-0.008，95%可信区间0.00-0.166，-0.002）。PTH0梯度是低钙血症的最佳预测指标（曲线下面积0.855，标准误-0.065，95%可信区间0.710至0.945，P值<0.001），而PTH1值是重度/临床低钙血症的更好预测指标（曲线下面积0.844，标准误-0.072，95%可信区间0.697至0.938，P值-0.001）。根据ROC曲线，预测低钙血症和重度/临床低钙血症的PTH0梯度和PTH1梯度临界值分别为60%和75%（低钙血症的敏感性为70%，特异性为90.5%；重度低钙血症的敏感性为65%，特异性为90.9%）。
PTH梯度可能是低钙血症的更好预测指标，PTH1梯度>75%与甲状腺切除术后重度/临床低钙血症的高风险相关。
