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.