Predictive value of 6 h postoperative parathyroid hormone level on permanent hypoparathyroidism in pediatric total thyroidectomy: a pilot study

OBJECTIVES: Transient hypocalcemia is a common complication after pediatric total thyroidectomy, while permanent hypoparathyroidism (PH) is relatively uncommon. To date there is no model to predict which patients will develop PH based on post-operative makers. We aim to identify pediatric patients who are at high risk of PH following thyroidectomy based on 6 h post-operative parathyroid hormone (PTH) value. METHODS: A retrospective review of 122 pediatric patients undergoing total thyroidectomy between 2016 and 2022 following implementation of a multidisciplinary team was performed. Outcome of interest was permanent hypoparathyroidism, defined as need for calcium supplementation at 6 months postoperatively. Receiver operating characteristic (ROC) analysis was used to determine PTH value at 6 h post-operative that was predictive of permanent hypoparathyroidism. RESULTS: Rates of permanent hypoparathyroidism reported are similar to those described in the literature with 12 patients (10.9%) developing PH. In patients who developed PH, mean 6 h postoperative PTH was 5.12 pg/mL. Mean 6 h postoperative PTH level in those who did not develop PH was 31.34 pg/mL (p<0.0001). The 6 h post-operative PTH value predictive for PH was ≤11.3 pg/mL. PTH cutoff of ≤11.3 pg/mL had a sensitivity of 100%, specificity of 72.2%, positive predictive value (PPV) of 27.0%, and negative predictive value (NPV) of 100%. CONCLUSIONS: 6 h postoperative PTH values were found to be predictive of permanent hypoparathyroidism in pediatric total thyroidectomy: a 6 h postoperative PTH level of >11.3 pg/mL excludes permanent hypoparathyroidism, but if PTH is ≤11.3 pg/mL at 6 h, approximately 1/3 of patients may persist with permanent hypoparathyroidism.