25-hydroxyvitamin D Deficiency is a Risk Factor for Symptoms of Postoperative Hypocalcemia and Secondary Hyperparathyroidism After Minimally Invasive Parathyroidectomy

Background: Patients with primary hyperparathyroidism who undergo minimally invasive parathyroidectomy (MIP) may have postoperative symptoms of hypocalcemia or secondary hyperparathyroidism. This study sought to identify factors predictive of these events.

Methods: Between 1998 and 2004, 190 patients with primary hyperparathyroidism underwent MIP with excision of a single adenoma. Age, gender, race, prior head and neck surgery, use of preoperative thyroid hormone or calcium-channel blockers, preoperative levels of calcium, 25-hydroxyvitamin D (25[OH]D) and intact parathyroid hormone (iPTH), the presence of osteopenia or osteoporosis, intraoperative iPTH levels, and adenoma weight were evaluated by univariate analysis as predictors of postoperative symptoms of hypocalcemia and secondary hyperparathyroidism.

Results: None of the following were predictors of postoperative symptoms of hypocalcemia: age, gender, race, prior head and neck surgery, preoperative medications, preoperative calcium and iPTH levels, osteopenia or osteoporosis, intraoperative iPTH levels, or adenoma weight. However, patients with postoperative symptoms of hypocalcemia had significantly lower preoperative 25[OH]D levels (P = .01). Further, higher preoperative iPTH levels (P < .01) and lower preoperative 25[OH]D levels (P = .05) were associated with secondary hyperparathyroidism postoperatively.

Conclusions: A low preoperative 25[OH]D level is associated with postoperative symptoms of hypocalcemia and secondary hyperparathyroidism in patients undergoing MIP. One might consider instituting empiric calcium supplementation postoperatively in patients with low 25[OH]D levels.