Calcium-lowering medications in patients with primary hyperparathyroidism: intraoperative findings and postoperative hypocalcemia

BACKGROUND: We analyzed how calcium-lowering medications (CLMs) influenced surgical findings in patients with primary hyperparathyroidism. METHODS: A retrospective review was conducted of 281 patients undergoing surgery for primary hyperparathyroidism. Logistic regression evaluated the relationship between CLM and surgical findings. A mixed-effects model determined the influence of CLMs on these curves. RESULTS: We found that CLM (P = .018) and a higher serum calcium level (P = .018) were variables making 4-gland hyperplasia less likely. Analysis of intraoperative parathyroid hormone (IOPTH) plots revealed that CLMs altered the kinetics (P = .043). However, the 2 groups did not differ in the number of measurements necessary for a 50% decrease in IOPTH levels. Multivariate logistic regression also revealed that patients taking more than one CLM had an increased association with postoperative hypocalcemia (P = .018). CONCLUSIONS: Although CLM contributed to differences in IOPTH curves, their use does not require changing standard IOPTH protocol but should alert the surgeon to the risk of postoperative hypocalcemia. (C) 2012 Elsevier Inc. All rights reserved.