Early prediction of hypocalcemia following thyroid surgery. A prospective randomized clinical trial.

PURPOSE The aim of this randomized-controlled trial was to validate the results of a previous prospective single-cohort observational study conducted in the same surgical unit regarding the use of concomitant intact parathyroid hormone (iPTH) and serum calcium measurement in predicting hypocalcemia after total thyroidectomy. METHODS From January 2014 to January 2015, 150 patients underwent total thyroidectomy in our department and were randomized into two groups. The experimental group was submitted to iPTH assay 6 h after surgery while the control group was submitted to a daily assay of serum calcium and phosphorus. Sensitivity and specificity of different serum measurements have been calculated using the receiver-operator characteristics (ROC) curve. RESULTS The prevalence of hypocalcemia was 14.25% in both groups. The assay of iPTH 6 h after surgery combined with the serum calcium assay 24 h after surgery yielded the highest diagnostic accuracy in predicting hypocalcemia using ROC curves, with 100% sensitivity and 100% specificity. CONCLUSIONS According to our previous study, the combined measurement of iPTH 6 h after surgery and of serum calcium 24 h after surgery are highly predictive of early postoperative hypocalcemia. These results are important in selecting the patients eligible for early discharge and those who need calcium and vitamin D supplementation.