Next-day Parathyroid Hormone as a Predictor of Post-thyroidectomy Hypocalcemia

ABSTRACT Aims Total thyroidectomy is significantly complicated by parathyroid dysfunction and hypocalcemia. These aspects impact the decision regarding the timing of discharge and quantum of calcium supplementation required. Therefore, we aimed at evaluating the accuracy of next-day parathyroid hormone (PTH) level as a predictor of post-thyroidectomy hypocalcemia. Secondly, we aimed at establishing our institution's postoperative PTH level, which can accurately predict the development of post-thyroidectomy hypocalcemia to help us ensure the safe and early discharge of patients. Materials and methods A prospective observational study of 50 continuous patients undergoing thyroidectomy was conducted at a tertiary hospital in South India. Postoperative blood samples were collected for estimation of PTH, calcium, albumin, and phosphorous. The data were collated and results analyzed using Stata I/C 10.1. Results A total of 30% (15/50) of the patients had postoperative hypocalcemia (serum calcium <8 mg/dL). Postoperative PTH was low (<8 pg/mL) in 40% (20/50) of patients. There was a significant association between PTH < 8 pg/mL and the presence of postoperative hypocalcemia (p = 0.029). The area under the receiver operating characteristic (ROC) curve was 0.7, and a next-day PTH of <6 pg/mL showed the highest sensitivity and specificity (83 and 60% respectively) for the development of postoperative hypocalcemia, with a positive predictive value (PPV) and negative predictive value (NPV) of 83 and 60 respectively. Conclusion The PTH assessment performed the day after surgery is an acceptable test to predict post-thyroidectomy hypocalcemia; PTH <6 pg/mL can be used as our institution's cutoff value. Department protocols for calcium and vitamin D supplementation following total thyroidectomy may be formulated based on the appropriately timed local postoperative PTH value to assist safe and early discharge of patients. Clinical significance Discharge protocols for patients undergoing thyroidectomy may be formulated based on the postoperative PTH values, thus enabling safe and early discharge of patients. How to cite this article Cherian AJ, Ramakant P, Paul TV, Abraham DT, Paul MJ. Next-day Parathyroid Hormone as a Predictor of Post-thyroidectomy Hypocalcemia. World J Endoc Surg 2016;8(3):203-207.