Preoperative vitamin D administration does not affect rates of post-thyroidectomy hypocalcaemia.

Objective: Hypoparathyroidism is a common complication of total thyroidectomy, and the role of vitamin D deficiency in post-thyroidectomy hypocalcaemia is unclear. This study evaluates the role of preoperative vitamin D supplementation in reducing rates of postoperative hypocalcaemia. Methods: This is a retrospective review of patients who underwent thyroidectomy before (n = 728) and after (n = 491) introduction of the routine preoperative active vitamin D in a tertiary medical centre. Patients were monitored for calcium support efficacy in managing hypocalcaemia. Results: Demographics, preoperative calcium levels, pathologies, and surgeries were similar between groups. Postoperative calcium levels showed a smaller decrease in the study group (-0.5 mg/dL vs -0.62 mg/dL, p = 0.04). Short-term postoperative hypocalcaemia (< 8 mg/dL) occurred in 15.7% (patients treated between 1996-2009) and 14.5% (patients treated between 2010-2016) (p = 0.54). Symptomatic and long-term hypocalcaemia rates were also comparable (p = 0.88, p = 0.6). Central neck dissection and goiter/thyrotoxicosis were significantly associated with hypocalcaemia. Conclusions: Pre-thyroidectomy vitamin D treatment does not prevent postoperative hypocalcemia. These findings suggest individualised calcium support strategies based on patient-specific factors post-thyroidectomy.