Objective: This study aims to determine whether preoperative supplementation of vitamin D reduces the incidence of hypocalcemia following total thyroidectomy.
Methods: Conducted in conformity with the PRISMA statement, a systematic review and meta-analysis of randomized clinical trials (RCTs) was performed, assessing postoperative hypocalcemia and symptomatic hypocalcemia.
Results: The search strategy identified 3808 relevant publications, with eight RCTs ultimately included. Across a total of 902 patients (median age: 48.9 years), four trials administered only vitamin D, three included both calcium and vitamin D, and one trial used vitamin D with calcium in both study arms. The pooled analysis showed a significantly reduced risk of postoperative hypocalcemia in patients receiving vitamin D supplementation (RR, 0.77; 95% CI, 0.62-0.96; p=0.02). When studies that included calcium were excluded, a similar reduction was observed (RR, 0.74; 95% CI, 0.57-0.96; p=0.03). Furthermore, a reduced risk of symptomatic hypocalcemia was noted (RR, 0.56; 95% CI, 0.34-0.93; p=0.023).
Conclusions: Preoperative administration of vitamin D—whether alone or with calcium—significantly lowers the risk of postoperative hypocalcemia and symptomatic hypocalcemia in patients undergoing total thyroidectomy. Future studies should explore optimal dosing strategies and identify patient subgroups that benefit the most
