Does Time Matter in Deficit of Calcium after Total Thyroidectomy in Subjects with Previous Bariatric Surgery?

Abstract

Background: Hypoparathyroidism-related hypocalcemia is a common complication after total thyroidectomy (TT), particularly if there is a history of prior bariatric surgery. However, it is still unknown if it is the surgery timing or the type of bariatric intervention that increases the risk of developing this complication. Methods: We compared the risk of hypocalcemia (serum calcium levels < 8 mg/dL) and hypoparathyroidism (both transient and permanent) between patients with restrictive procedures (LSG and GB) and patients without a history of obesity surgery in the immediate post-operative period and after 12 months. Hypoparathyroidism was considered permanent if the plasma parathyroid hormone (PTH) levels at 6 months were less than 15 pg/mL and the patient still required oral calcium (calcium carbonate) and vitamin D supplementation, in addition to the supplements that were taken routinely before thyroidectomy. Results: From the 96 patients who underwent TT, 50% had a history of bariatric surgery: 36 LSG and 12 GB. The risk of hypocalcemia was similar in patients with a history of restrictive procedures (31.35%) and in controls (25%) (p = 0.49). Furthermore, hypocalcemia risk was similar between patients with a history of LSG (30.5%) and GB (33%) (p = 0.85). The prevalences of transient and permanent hypoparathyroidism were similar between patients with a history of restrictive procedures and in controls; similarly, no differences were detected between subjects undergoing LSG and GB. Conclusions: Restrictive bariatric surgery (LSG and GB) is not a risk factor for post-thyroidectomy hypocalcemia and hypoparathyroidism and thus did not require a different perioperative supplementation protocol compared to subjects without history of bariatric surgery undergoing TT.

Keywords: bariatric surgery; chrononutrition; hypocalcemia; hypoparathyroidism; obesity; thyroidectomy.