Preoperative Vitamin D Supplementation to Reduce Hypocalcemia Following Total Thyroidectomy: Systematic Review and Meta-Analysis of Randomized Clinical Trials

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 (RCT) was performed assessing postoperative hypocalcemia and postoperative symptomatic hypocalcemia. Results: The search strategy yielded 3808 potentially relevant publications, with eight RCTs ultimately included. These eight trials included a total of 902 patients (22.73% male, n = 205/902), with a median age of 48.9 years (95% CI, 43.5-53.5). Four trials administered only vitamin D in the interventional arm, three trials administered both calcium and vitamin D in the interventional arm, and one trial administered vitamin D in the interventional arm and calcium in both arms. Pooled results from the eight included trials showed a reduced risk of postoperative hypocalcemia in the intervention arm (RR, 0.77; 95% CI, 0.62-0.96; p = 0.02). When excluding the studies that administered calcium supplements in addition to vitamin D, the pooled results showed a similar reduced risk of postoperative hypocalcemia (RR, 0.74; 95% CI, 0.57-0.96; p = 0.03). Analysis of six trials reporting the incidence of postoperative symptomatic hypocalcemia (n = 564) showed a reduced risk in the vitamin D arm, with or without calcium, compared to the control arm (RR, 0.56; 95% CI, 0.34-0.93; p = 0.023). Conclusions: Our findings suggest that preoperative vitamin D administration, with or without calcium carbonate, significantly reduces the risk of postoperative hypocalcemia and symptomatic hypocalcemia in patients undergoing total thyroidectomy.