The Effect of Hypomagnesemia on Refractory Hypocalcemia after Total Thyroidectomy: A Single-Center Prospective Cohort Study

Abstract

Background: Hypomagnesemia is known to impede hypocalcemia correction. This prospective observational study aimed to evaluate the impact of serum magnesium levels on the development of refractory hypocalcemia, which remains a concerning problem after total thyroidectomy (TT). Subjects and Methods: Consecutive subjects (n = 312; mean age = 38.4 [range: 13–83] years; M:F = 62:250) undergoing TT for benign or malignant thyroid diseases were evaluated for serum corrected-calcium (8.4–10.4 mg/dL), magnesium (1.7–2.4 mg/dL), intact parathormone (iPTH), and 25-hydroxycholecalciferol (25OHD) levels preoperatively, at 48-h and 6-month post-TT. Results: Postoperatively, 98 subjects (31.4%) exhibited transient hypocalcemia, 96 (30.8%) had hypomagnesemia, and 52 (16.7%) had refractory hypocalcemia. Preoperatively, 38 subjects (12.2%) had asymptomatic hypocalcemia and 77 (24.7%) had hypomagnesemia. In multivariate logistic regression analysis, independent risk factors of transient hypocalcemia were hyperthyroidism (odd's ratio [OR]: 5.6), 48-h iPTH (OR: 3.2), 48-h magnesium (OR: 2.7), preoperative 25OHD (OR: 0.96), and preoperative calcium (OR: 0.5; each P 10.5% within 48-h post-TT are associated with refractory hypocalcemia, which necessitates correction of both the deficiencies for prompt resolution of symptoms.

Keywords

• hypomagnesemia
• magnesium
• post-thyroidectomy hypocalcemia
• refractory hypocalcemia
• thyroidectomy