Summary:
In adults undergoing total thyroidectomy for benign thyroid disease including symptomatic nodular goitre or Graves’ disease (n=62), preoperative supplementation with calcium carbonate 500 mg three times daily and magnesium carbonate 300 mg once daily for 2 weeks before surgery modestly improved postoperative quality of life with earlier recovery in Graves’ disease patients and numerically reduced hypocalcemia rates (19.4% vs 25%) compared to standard care without preoperative supplementation, though it was associated with non-statistically significant differences in hypoparathyroidism rates (16% vs 23%) and no correlation between baseline vitamin D deficiency and hypocalcemia risk.
| PICO | Description |
|---|---|
| Population | Adults (n=62) undergoing total thyroidectomy for benign thyroid disease, including symptomatic nodular goitre and Graves’ disease. |
| Intervention | Preoperative supplementation with calcium carbonate 500 mg three times daily and magnesium carbonate 300 mg once daily for 2 weeks before scheduled thyroidectomy. |
| Comparison | Control group receiving standard preoperative care without calcium or magnesium supplementation. |
| Outcome | Both groups showed postoperative QoL improvement, with earlier benefit in the intervention group among Graves’ disease patients. Hypocalcemia occurred in 19.4% of supplemented vs 25% of control patients; hypoparathyroidism in 16% vs 23%. Differences were not statistically significant. Baseline vitamin D deficiency (66.7%) did not predict hypocalcemia risk. |
Clinical Context
Postoperative hypocalcemia is the most common complication following total thyroidectomy, occurring in 20-30% of patients and resulting from surgical trauma to or inadvertent removal of the parathyroid glands. While most cases are transient, symptomatic hypocalcemia causes significant morbidity including perioral numbness, paresthesias, muscle cramps, and in severe cases, tetany and cardiac arrhythmias. Permanent hypoparathyroidism requiring lifelong calcium and vitamin D supplementation occurs in 1-3% of thyroidectomies.
Prevention strategies have focused primarily on surgical technique, but preoperative optimization represents an underexplored approach. The rationale for preoperative calcium and magnesium supplementation includes building calcium stores to buffer against postoperative parathyroid dysfunction and ensuring adequate magnesium for optimal PTH secretion and action. Magnesium deficiency impairs both PTH release and peripheral PTH responsiveness, potentially exacerbating hypocalcemia when parathyroid function is compromised.
This study tested whether a simple, inexpensive preoperative supplementation regimen could reduce postoperative hypocalcemia and improve quality of life recovery in patients undergoing total thyroidectomy for benign disease. The inclusion of both nodular goitre and Graves’ disease patients allowed assessment of whether underlying thyroid pathology influences response to supplementation.
Clinical Pearls
1. Numerically Lower Hypocalcemia but Not Statistically Significant: The reduction in hypocalcemia from 25% to 19.4% and hypoparathyroidism from 23% to 16% suggests a potential benefit, but the study was underpowered to detect statistical significance. A larger trial would be needed to confirm whether these trends represent true effects.
2. Quality of Life Benefits May Differ by Diagnosis: Graves’ disease patients showed earlier QoL improvement with supplementation compared to controls, while nodular goitre patients showed similar trajectories regardless of supplementation. This suggests Graves’ patients might benefit more, possibly due to their higher metabolic demands or different baseline nutritional status.
3. Vitamin D Deficiency Was Common but Not Predictive: Despite 66.7% of patients having vitamin D deficiency at baseline, this did not correlate with postoperative hypocalcemia risk. This challenges assumptions that vitamin D status is a major determinant of post-thyroidectomy calcium complications and suggests other factors predominate.
4. Low-Cost, Low-Risk Intervention: Calcium and magnesium supplementation is inexpensive, widely available, and carries minimal risk when used for 2 weeks preoperatively. Even modest benefits could justify routine use given the favorable risk-benefit profile.
Practical Application
Consider recommending preoperative calcium (500 mg three times daily) and magnesium (300 mg daily) supplementation for 2 weeks before scheduled total thyroidectomy. While definitive efficacy is not established, the low cost and safety profile make this a reasonable preventive strategy, particularly for Graves’ disease patients who may show earlier quality of life recovery.
Do not rely on baseline vitamin D levels to risk-stratify for postoperative hypocalcemia—this study found no predictive value. Continue standard postoperative calcium monitoring and symptom assessment regardless of preoperative supplementation status. Maintain low thresholds for treating symptomatic hypocalcemia.
Counsel patients that preoperative supplementation may reduce but will not eliminate hypocalcemia risk. Postoperative calcium and vitamin D supplementation remains standard practice for most patients following total thyroidectomy until parathyroid function recovery is confirmed.
Broader Evidence Context
This study adds to limited evidence on preoperative optimization strategies for thyroidectomy. Most research has focused on postoperative management protocols including routine calcium supplementation after surgery rather than preoperative preparation. The concept of “prehabilitation” before surgery is gaining attention across surgical specialties, and this study represents an application to endocrine surgery.
Current guidelines do not specifically recommend preoperative calcium/magnesium supplementation, though they acknowledge the importance of identifying and correcting vitamin D deficiency preoperatively. Larger trials would be needed to change practice guidelines.
Study Limitations
Small sample size (n=62) resulted in inadequate statistical power to detect clinically meaningful differences in hypocalcemia rates. The study was not blinded, introducing potential bias in QoL assessments. The specific contribution of magnesium versus calcium cannot be determined from this combined intervention. Follow-up duration for permanent hypoparathyroidism assessment was not detailed.
Bottom Line
Preoperative calcium and magnesium supplementation before total thyroidectomy shows promising but non-significant trends toward reduced hypocalcemia and faster quality of life recovery, particularly in Graves’ disease patients, warranting larger confirmatory trials of this low-cost, low-risk preventive strategy.
Source: Navid Tabriz, et al. “Impact of Preoperative Calcium and Magnesium Supplementation on Quality of Life and Hypocalcemia Post-Thyroidectomy.” Read article
