Objective: To determine whether perioperative vitamin D levels are predictive of postoperative hypocalcemia in patients receiving thyroidectomy.
Study design: Single center retrospective study.
Subjects and methods: This study included all patients receiving total or completion thyroidectomy between January 2007 and March 2017 at a single tertiary care hospital. 25-Hydroxyvitamin D (25[OH]D) levels were measured within 42 days prior to surgery or 1 day postoperatively. Hypocalcemia was defined as an adjusted serum calcium <8.0 mg/dL (based on albumin levels) or symptomatic hypocalcemia. Univariate analysis was performed with a 2-sample t test and chi-square test, while multivariate analysis was performed with logistic regression analysis to determine whether perioperative 25(OH)D level is a predictor of postoperative hypocalcemia.
Results: A total of 517 subjects were included in the study, 15.7% (n = 81) of whom experienced postoperative hypocalcemia with a mean ± SD serum calcium level of 7.6 ± 0.5 mg/dL as compared with 8.9 ± 0.5 mg/dL in the normocalcemic population (P < .01). The mean 25(OH)D level for patients with hypocalcemia was 24.4 ± 12.0 ng/mL as compared with 27.5 ± 12.2 ng/mL in patients with normocalcemia (P = .038). Subjects who were hypocalcemic experienced a significantly longer hospital stay (2.9 ± 2.5 vs 1.4 ± 1.1 days, P < .01). After adjusting for preoperative calcium, age, and performance of a neck dissection, subjects with a 25(OH)D level <30 ng/mL were significantly associated with postoperative hypocalcemia (odds ratio, 1.9; P = .041; 95% CI, 1.0-3.3).
Conclusion: Using a single-center retrospective study design, we demonstrated that 25(OH)D level is a significant predictor of postoperative hypocalcemia after thyroidectomy.
Keywords: complications; hypocalcemia; thyroid disease; thyroidectomy; vitamin D.