Evaluation of the incidence and risk factors of hypocalcemia and hypoparathyroidism after total and partial thyroidectomy

Background: Thyroidectomy techniques have evolved over the last 150 years. Postoperative hypocalcemia and hypoparathyroidism are common. Previous studies have focused on identifying risk factors for hypocalcemia and hypoparathyroidism after thyroid surgery, with inconclusive results. To address this, we aimed to conduct a study to assess the incidence and risk factors of postoperative calcium and hypoparathyroidism after total and subtotal thyroidectomy. Methods: Patients were included over a one-year period. The data collected included information on demographic characteristics, medical history, surgical details, pre- and post-operative calcium and parathyroid hormone levels, neck dissection, type of disease, and surgery. The statistical analyses utilized paired t-tests, Wilcoxon signed-rank tests, and binary logistic regression in R Studio. Results: The study included 39 patients with an average age of 61.5. Most patients were male (35 out of 39, 89.7%). Three patients underwent partial thyroidectomy. After the operation, the levels of calcium, corrected calcium, PTH, albumin, and phosphorous significantly decreased. Factors that varied statistically between patients with normal and hypocalcemia were PTH and magnesium levels. Several factors emerged as statistically significant predictors for post-thyroidectomy hypocalcemia and hypoparathyroidism. Factors that statistically predicted the development of hypocalcemia were parathyroidectomy, pre and postoperative parathyroid hormone level, corrected calcium levels, neck dissection, preoperative vitamin D, and postoperative magnesium levels. Besides, neck dissection and pre-operative vitamin D levels predicted the development of hypoparathyroidism. Conclusion: By assessing pre-operative PTH and corrected calcium levels and adopting a customized surgical approach to minimize parathyroid gland damage, we can lower the risk of postoperative hypocalcemia.