A postoperative parathyroid hormone-based algorithm to reduce symptomatic hypocalcemia following completion/total thyroidectomy: A retrospective analysis of 591 patients

Background: An institutional protocol for selective calcium/calcitriol supplementation after completion/total thyroidectomy was established based on the 4-hour postoperative parathyroid hormone level. The aim of this study was to evaluate the outcomes of this protocol 5 years after implementation. Methods: All patients who underwent completion/total thyroidectomy from January 2012 to December 2016 were reviewed. Predictors of a 4-hour parathyroid hormone level <10 pg/mL and symptomatic hypocalcemia were assessed. Results: Of 591 patients, 448 (76%) had a 4-hour parathyroid hormone >= 10, 72 (12%) had a 4-hour parathyroid hormone of 5-10, and 71 (12%) had a 4-hour parathyroid hormone <5. Hypocalcemic symptoms were infrequent (30/448, 7%) if the 4-hour parathyroid hormone was >= 10; 56% (40/71) of those with a 4-hour parathyroid hormone <5 reported symptoms. With 4-hour parathyroid hormone of 5-10, symptoms were reported in 32 of 72 (44%) patients; supplementation at discharge included calcium (n=55, 76%), calcium and calcitriol (n=12, 17%), or none (n=5, 7%). Ten patients subsequently received calcitriol for persistent symptoms. On multivariate analysis, predictors of 4-hour parathyroid hormone <10 included incidental parathyroidectomy, malignancy, and thyroiditis; predictors of hypocalcemic symptoms included age <55 and 4-hour parathyroid hormone <10. Conclusion: After completion/total thyroidectomy, patients with a 4-hour parathyroid hormone >= 10 can be safely discharged without routine supplementation. The addition of calcitriol to calcium supplementation should be strongly considered for patients with a 4-hour parathyroid hormone of 5-10. (C) 2018 Elsevier Inc. All rights reserved.