Change in parathyroid hormone levels from baseline predicts hypocalcemia following total or completion thyroidectomy.

Background: This study aims to identify the strongest predictor of postoperative hypocalcemia following thyroid surgery.

Methods: Study of patients who underwent total/completion thyroidectomy. No patients received postoperative calcium supplementation. Demographic and perioperative data were collected including preoperative baseline parathyroid hormone (PTH) levels, PTH levels at 30 min and 6 h post-excision, and 18 h post-excision calcium levels.

Results: Of 124 patients studied, 20.2% developed temporary hypocalcemia (Ca <8.5 mg/dL at 18 h post-excision). In multivariate analyses, absolute PTH levels at 30 min and 6 h post-excision as well as change in PTH from baseline at 30 min and 6 h post-excision were statistically significantly associated with postoperative hypocalcemia. Per 10 units decrease in PTH from baseline at 30 min post-excision, the risk of developing temporary hypocalcemia increases by 17%.

Conclusion: Absolute PTH levels and change in PTH from baseline at 30 min and 6 h post-excision predict hypocalcemia after total or completion thyroidectomy.