Routine Low-dose Calcium and Vitamin D Supplementation for Preventing Symptomatic Postthyroidectomy Hypocalcemia

The present study investigated the effect of routine calcium and vitamin D supplementation and tried to find the predictors for postoperative hypocalcemia in patients with thyroid cancer. Demographic data, including age, sex, pathologic features, and postoperative laboratory test results were analyzed, as was the development of symptomatic hypocalcemia, defined as an ionized calcium concentration below 4.6 mg/dL (normal range, 4.6-5.4 mg/dL) associated with hypocalcemic symptoms. Hypocalcemia was considered permanent in patients who required calcium supplementation for longer than 6 months after thyroidectomy.

Serum concentrations of PTH and ionized calcium were measured 1 and 14 days postoperatively. Patients in the routine calcium group received oral supplements of 1,500 mg/day elemental calcium and 1,000 IU/day cholecalciferol for 2 weeks, beginning on the first postoperative day (POD) to the 14th POD, whereas patients in the control group received no supplementation. If symptomatic hypocalcemia developed, patients in both groups received 2.0 g of intravenous calcium, followed by oral supplementation with 3,000-4,000 mg/day elemental calcium and 1,000-2,000 IU/day cholecalciferol up to the 14th POD. If hypocalcemic symptoms were persistent or worsening 2 hours after calcium administration, patients were administered another intravenous calcium supplementation.