New Formula Gauges IV Calcium Need After Parathyroidectomy

Miriam E. Tucker, for Medscape

May 31, 2022

Researchers published the study covered in this summary on as a preprint that has not yet been peer reviewed.

Key Takeaways

  • Researchers have developed and validated a predictive model to estimate the amount of postoperative intravenous (IV) calcium supplementation required for patients with secondary hyperparathyroidism (SHPT) following total parathyroidectomy (tPTX).

Why This Matters

  • While tPTX is acknowledged as the most effective treatment for patients with SHPT, it can result in severe postoperative hypocalcemia that can be difficult to accurately predict and treat. Currently, no unified standards exist to guide the treatment of patients with SHPT who develop postoperative hypocalcemia following tPTX.

  • Hypocalcemia is a common complication that can develop within 24-48 h after tPTX resulting in clinical symptoms including numbness and convulsions of the hands and feet, arrhythmia, epilepsy, a positive cheek reaction, severe asphyxia, and even cardiac arrest. However, only about 30% of affected patients exhibit clinical symptoms.

  • After prospective assessment, the new model and the guidance it provides on the amount of postoperative IV calcium to administer has the potential to guide clinical decision-making about the route of postoperative calcium supplementation (subclavian vein, central vein catheterization, external jugular vein, etc), and whether any other preoperative or postoperative interventions may be appropriate.

  • The findings provide a robust theoretical foundation for future development of a standardized calcium supplementation strategy that is able to reduce complications and improve patient outcomes, say the authors.

Study Design

  • Data were analyzed from 490 adults with SHPT (228 men and 262 women) treated at a single hepatobiliary surgery department in China in 2015-2021.

Key Results

  • Hypocalcemia developed in 73% of the patients.

  • A multivariate analysis identified four factors that significantly linked with need for supplemental calcium, which collectively accounted for 41% of the variation in this parameter.

  • Sex and free thyroxine levels had an inverse correlation with calcium need, while serum ferritin and alkaline phosphatase had positive correlations.

  • The complete predictive model is:
    IV calcium supplementation = 1235.561-158.547 * sex (men = 0, women = 1) + 0.141 * serum ferritin + 0.442 * alkaline phosphatase - 494.055 * free thyroxin


  • The authors did not identify study limitations.


  • The study received no commercial funding.

  • None of the authors had disclosures.

This is a summary of a preprint research study, "Construction of a predictive model of intravenous calcium supplementation needs following total parathyroidectomy in patients with secondary hyperthyroidism" written by researchers at Northern Theater General Hospital, Shenyang, Liaoning Province, China, on Research Square and provided to you by Medscape. This study has not yet been peer reviewed. The full text of the study can be found on


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