The role of perioperative vitamin D measurement after total thyroidectomy as a predictor of hypocalcemia

Background: Temporary hypocalcemia, a common occurrence after total thyroidectomy, affects up to 35% of patients, presenting mild to severe symptoms such as paresthesia, tingling, cramps, tetany, and convulsion. Aim: To discuss the relation between vitamin D and postoperative hypocalcemia in patients undergoing total thyroidectomy and to determine the optimal vitamin D threshold level to reduce hypocalcemia risk, enabling judicious and goal-directed vitamin D replacement. Patients and Methods: This prospective study was conducted on 200 patients with hypocalcaemia underwent total thyroidectomy in Kasr El-Ainy University Hospitals, Faculty of Medicine, Cairo University from 2023. Results: Age, female patients, alkaline phosphatase, and hospital stay were significantly higher in patients who developed postoperative Ca less than or equal to 8 mg/dl than those who developed postoperative Ca greater than 8 mg/dl (P<0.00]). Preoperative and postoperative Ca and preoperative 25-hydroxyvitamin D (OHD) were significantly lower in patients who developed postoperative Ca less than or equal to 8 mg/dl than those who developed postoperative Ca greater than 8 mg/dl (P<0.00]). Albumin and creatinine were insignificantly different between patients who developed postoperative Ca less than or equal to 8 mg/dl and those who developed postoperative Ca greater than 8 mg/dl. Conclusion: Patients who developed postoperative hypocalcemia had significantly lower preoperative 25-OHD levels compared to those who did not develop hypocalcemia. Additionally, older age and female sex were identified as risk factors for postoperative hypocalcemia. The study also demonstrated a positive correlation between postoperative calcium levels and preoperative 25-OHD levels, suggesting that adequate vitamin D status may play a protective role against postoperative hypocalcemia.