Serum calcium relative decline as a predictor of post thyroidectomy hypocalcaemia.

Abstract

Objectives: To assess the value of corrected calcium decline at 6 hours as a predictor of hypocalcaemia post total thyroidectomy by comparing it to the currently widely used intact parathyroid hormone.

Methods: A retrospective cohort study of patients who underwent total thyroidectomy from January 2016 to February 2020. Serum intact parathyroid hormone and corrected calcium data pre-operatively and 6 hours post-operatively were obtained. Receiver operating characteristic curves were used to compare corrected calcium decline at 6 hours versus 6 hours for relative intact parathyroid hormone decline as predictors of hypocalcaemia, and the area under the curve for each metric was reported.

Results: Patients included in this analysis totalled 209. The receiver operating characteristic analysis suggested that corrected calcium decline at 6 hours has a similar predictive value to 6 hours relative intact parathyroid hormone. The areas under the curves for predicting hypocalcaemia were 0.797 for corrected calcium decline at 6 hours and 0.737 for 6 hours relative intact parathyroid hormone, but the difference (0.06) was not statistically significant.

Conclusions: Our results suggest that corrected calcium decline at 6 hours has a similar predictive value to 6 hours relative intact parathyroid hormone and hence has the potential to predict post-operative hypocalcaemia.