Published: 2020-11-27

Serum calcium slope is a predictor of post-thyroidectomy hypocalcemia

Veena Vasudev, Anil Kumar A. V.


Background: Hypocalcemia is a common complication following thyroidectomy. The effects of hypocalcemia can range from simple numbness to life-threatening seizures. Barring stridor, haemorrhage and hypocalcemia, other complications of thyroidectomy are not seriously morbid and hence patients can be sent home. This study sought to determine whether early postoperative calcium levels can predict hypocalcemia following thyroidectomy, to help decide on early discharge.

Methods: This was a prospective cohort study, conducted between July 2016 and June 2017 among 80 consecutive patients who underwent total thyroidectomy in our department. Serum calcium values were obtained pre-operatively and at 6 and 24 hours post-operatively. Serum calcium slopes were calculated and the receiver operating characteristic curve constructed to evaluate the accuracy of risk prediction.

Results: The mean total calcium levels of patients with hypocalcemia were significantly lower than the levels of the normocalcemic group. The slope of change between total calcium measurements at 6 and 24 hours in patients with hypocalcemia was found to be significantly steeper than the slope in the case of normocalcemic patients.

Conclusions: It is possible to predict post-thyroidectomy hypocalcemia based on the characteristics of the early post-operative serum calcium slope. On the basis of the slope’s features, all patients except those at risk can be safely discharged home early. This can cut down on the patients’ total cost of treatment as well as save unnecessary wastage of health resources.


Hypocalcemia, Parathyroid, Serum calcium, Thyroidectomy

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