Department of Surgery, Jordan Hospital, Amman, Jordan.
Department of Surgery, Jordan Hospital, Amman, Jordan; Department of Surgery, Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania.
Endocr Pract. 2021 Sep;27(9):925-933. doi: 10.1016/j.eprac.2021.02.014. Epub 2021 Feb 27.
To define optimal intact parathyroid hormone (iPTH) cut-off threshold predictive of hypocalcemia after total thyroidectomy for safe and effective postoperative management.
This prospective single center study was done in 2 phases. In phase I, predictors of symptomatic hypocalcemia were analyzed and the receiver operating characteristic curve was used to define the optimal iPTH cut-off threshold predictive of hypocalcemia. Phase II studied giving prompt prophylactic supplemental calcium and vitamin D to all patients who had iPTH levels below the calculated threshold, while phase I patients were given prompt selective supplementation if they had postoperative hypocalcemia or symptoms.
Univariate analysis of patients in phase I showed that postoperative iPTH was the only significant variable that can predict symptomatic hypocalcemia. Using receiver operating characteristic curve and Youden index, the confirmed optimal cut-off threshold predictive of hypocalcemia was iPTH 19.95 pg/mL, with area under the curve of 0.903, 100% sensitivity, negative predictive value, and highest Youden index, while iPTH 15 pg/mL and iPTH 10 pg/mL were less optimal. Symptomatic hypocalcemia occurred in 30% of the phase I cohort who received selective supplementation versus 3% of those in the phase II cohort who received prophylactic supplementation. Return to emergency department and need for intravenous calcium were also significantly better in phase II.
iPTH cut-off for post-thyroidectomy hypocalcemia was 19.95 pg/mL. Low-risk patients were discharged with no supplementation while all high-risk patients received prompt calcium and vitamin D supplementation, which led to effective hypocalcemia management and safe 24-hour discharge.
定义最佳的完整甲状旁腺激素（iPTH）截断值，以预测全甲状腺切除术后低钙血症，从而实现安全有效的术后管理。
本前瞻性单中心研究分为 2 个阶段进行。在第 1 阶段，分析了症状性低钙血症的预测因素，并使用受试者工作特征曲线来定义预测低钙血症的最佳 iPTH 截断值。第 2 阶段研究对所有 iPTH 水平低于计算出的阈值的患者给予及时预防性补充钙和维生素 D，而第 1 阶段的患者如果术后出现低钙血症或症状，则给予及时的选择性补充。
第 1 阶段患者的单因素分析显示，术后 iPTH 是唯一能预测症状性低钙血症的显著变量。使用受试者工作特征曲线和 Youden 指数，确定的预测低钙血症的最佳截断值为 iPTH 19.95 pg/mL，曲线下面积为 0.903，灵敏度为 100%，阴性预测值最高，Youden 指数最高，而 iPTH 15 pg/mL 和 iPTH 10 pg/mL 则不太理想。接受选择性补充的第 1 阶段队列中有 30%的患者发生了症状性低钙血症，而接受预防性补充的第 2 阶段队列中有 3%的患者发生了症状性低钙血症。第 2 阶段患者返回急诊室和需要静脉补钙的情况也明显更好。
甲状旁腺切除术后低钙血症的 iPTH 截断值为 19.95 pg/mL。低危患者无需补充即可出院，而所有高危患者均及时补充钙和维生素 D，从而实现了有效的低钙血症管理和安全的 24 小时出院。
