Incidence, factors enabling to predict and management of hypocalcemia following total thyroidectomy for thyroid cancer: A prospective observational study.

Abstract

e18127 Background: Hypocalcemia (transient) is the most common complication following total thyroidectomy. It may or may not be accompanied by hypoparathyroidism. Various factors, such as preoperative Vitamin D, magnesium and phosphorus levels and the need to perform central compartment dissection may be associated with this complication. Methods: In this prospective observational study (CTRI/2020/12/030092) conducted between March 2022 to October 2024, all patients diagnosed with thyroid cancer who were to undergo total thyroidectomy with or without neck dissection as per the tumour board decision were included. Preoperative serum vitamin D, magnesium phosphorus and calcium measurements were done in all patients in addition to the routine investigations. Postoperatively, serum parathormone was measured on day 1 morning, and serum calcium and albumin were measured on Day 2 morning. Patients were managed for postoperative hypocalcemia as per standard practice. Results: A total of 338 patients were included in the final analysis. The median age of the patients was 40.5 years. One hundred and six patients (31.4%) presented with a palpable neck node in our cohort, and 113 (33.4%) patients had a thyroid nodule >4 cm in size. A large majority of our patients had subnormal levels of vitamin D levels (n=300,90.2%) with a median value of 16.2 ng/ml (1.31-85.10 ng/ml). All these patients received corrections as per the standard practice. The central compartment and lateral neck were addressed in 64% of the patients. The incidence of (transient) hypocalcemia was 31.4% (n=106), out of which 44 patients had only biochemical hypocalcemia and 62 patients had both clinical and biochemical hypocalcemia. Preoperative serum vitamin D, magnesium and phosphorus levels did not have any influence on the patients developing (transient) hypocalcemia. Patients with postoperative day 1 serum parathormone levels of < 15 pg/ml developed clinical & biochemical (transient) hypocalcemia.[p<0.001,OR 2.74(1.219-4.242)]. Patients having a calcium delta (Preoperative calcium-postoperative day 2 corrected serum calcium) of >1.36 mg/dl and day 2 PTH levels < 5 pg/ml often required parenteral corrections. The median duration of hospital stay of our patients was 5 days. There was an increase in the duration of hospital stay in patients with (transient) hypocalcemia (p=0.016) and more so who required parenteral correction (p=0.015). Overall calcium delta >1.09,[p<0.001,17.604(9.560-32.416)], postoperative day 1 serum parathormone <15pg/ml [p<0.001,2.281 (1.22-4.257)] and ≤2 parathyroid saved [p=0.49,2.55(1.004-6.474)] influenced the duration of hospital stay. Conclusions: The incidence of (transient) hypocalcemia in our cohort of patients was 31.4% and it does influence the duration of hospital stay of the patients. Preoperative vitamin D, magnesium and phosphorus levels did not have any influence on the incidence of postoperative (transient) hypocalcemia. Clinical trial information: CTRI/2020/12/030092 .