The role of preoperative vitamin D and calcium in preventing post-thyroidectomy hypocalcaemia: a systematic review

The thyroid gland plays an important endocrine function regulating metabolism, growth and development. A variety of benign and malignant conditions necessitate surgical removal of the thyroid gland, either in its entirety, or partially. Thyroidectomy is the most commonly undertaken endocrine surgery. Hypocalcaemia, occurring at a rate of approximately 25%, is the most common complication following total thyroidectomy. Hypocalcaemia can increase healthcare costs requiring further investigations, treatment and delaying discharge. Severe hypocalcaemia can be potentially life threatening. It has been demonstrated that routine post-operative supplementation with Vitamin D and calcium, can reduce post-operative hypocalcaemia, at present it is unclear whether preoperative supplementation has a similar effect.

This systematic review includes randomised controlled trials on human adult subjects, who received preoperative Vitamin D and/or calcium, and which studied the effect on post-operative hypocalcaemia following total or near total thyroidectomy. There were no restrictions in respect of post-operative supplementation regimen. Studies were limited to those published in English.

Seven of the eleven trials demonstrated a reduction in either laboratory or clinical hypocalcaemia with preoperative supplementation. This benefit was most likely to be seen when postoperative supplementation was performed on an as needed basis. IV calcium was required to treat resistant or severe hypocalcaemia, in five of the eleven trials, in each of these five trials, rates of IV replacement were lower in the preoperative supplementation group.

The use of preoperative Vitamin D, with or without calcium, may provide a modest reduction in the incidence of laboratory and clinic hypocalcaemia following total or near total thyroidectomy. There is a trend toward a reduced requirement for IV calcium with preoperative supplementation. Larger robust randomised trials are needed to provide a definitive answer. Preoperative supplementation can be considered in patients undergoing total or near total thyroidectomy.