Is Decline Rate of Intact Parathyroid Hormone Level a Reliable Criterion for Early Discharge of Patients after Total Thyroidectomy?

Abstract

INTRODUCTION: Parathyroid dysfunction leading to symptomatic hypocalcemia is not uncommon following a total thyroidectomy and is often associated with significant patient morbidity and a prolonged hospital stay. The current study aimed at evaluating the comparative predictive role of serum calcium and intact parathyroid hormone (iPTH) for post-thyroidectomy hypocalcemia. MATERIALS AND METHODS: This prospective study was performed in 83 consecutive patients undergoing total thyroidectomy. Laboratory data such as serum calcium, vitamin D level, serum iPTH and serum phosphorus levels before surgery, postoperative calcium, and PTH levels measured after 1 and 6 hours and on the first postoperative day (1POD) were recorded. RESULTS: Among the 83 patients, the mean (SD) age was 45.87 (12.57) years (range, 21-72 years); 70 (84.3) patients were female. Final pathology was benign for 47 (56.6) patients and malignant for 36 (43.4) patients. In total, lymph node dissections were performed in 19 subjects (22.9). On histological examination of the specimens, the parathyroid gland was found to have been removed inadvertently in 13 (15.7) cases. In total, 35 (40.9) patients developed hypocalcemia after thyroidectomy; receiver operating characteristic (ROC) analysis showed that a cut-off value of 15.39 pg/ml for iPTH, with a decline rate of 73 1 hour after thyroidectomy is a significant predictor of hypocalcemia (area under the curve AUC, 0.878; 95% confidence interval CI, 0.79-0.96, P<0.0001) compared with calcium <8 mg/dl (2 mmol/L) with AUC=0.639; 95% CI, 0.51-0.76); P=0.067). CONCLUSION: The current study showed that the decline rate in iPTH is a more reliable factor for hypocalcemia after total thyroidectomy than serum calcium. Patients with a decline rate <73% in iPTH could be discharged at 1POD without supplementation.