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

ABSTRACT 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. Level of Evidence 1.