Authors' reply: Systematic review and meta-analysis of predictors of post-thyroidectomy hypocalcaemia (Br J Surg 2014; 101: 307-320)
SirThis is a systematic review aimed at identifying predictors of postthyroidectomy hypocalcaemia (PTH) that have been studied previously and published in the literature. The association between high postoperative phosphate and postoperative hypocalcaemia is presented in Table 1. This is not mentioned in the abstract and not detailed in the discussion as the focus was on factors identified as significant in multivariable analyses.All three papers referred to by the authors in their discussion on serum phosphate have been included in this review. We agree that phosphate is potentially a good predictor of PTH in patients without vitamin D deficiency 1 . However, no association was found between serum phosphate and PTH in patients with vitamin D deficiency 1 . Although relatively inexpensive, the use of phosphate would also require measurement of vitamin D levels.In addition, the clinical value of postoperative phosphate in predicting transient hypocalcaemia is unclear, as the changes in phosphate seem to occur after the first postoperative day 2 .In contrast to the authors' interpretation, Pattou and colleagues 3 did not find an association between early phosphate levels (within 5 days of surgery) and permanent hypocalcaemia. They did, however, find an association between delayed 'high phosphate' and permanent hypocalcaemia 3 , findings similar to those of Pisanu et al. 4 .All statements in the results and conclusion sections of the abstract are based on evidence presented in the text.