In the Journals

Researchers identify factors associated with hypocalcemia after thyroidectomy

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November 25, 2014

A low postoperative intact parathyroid hormone level, female gender and presence of malignant neoplasm all independently predicted hypocalcemia after total thyroidectomy, according to results of a retrospective study.

“These variables should all be taken into account when decisions are being made about how to most effectively prevent or manage postoperative hypocalcemia,” Salem I. Noureldine, MD, of the division of head and neck endocrine surgery and the department of otolaryngology — head and neck surgery at Johns Hopkins University School of Medicine, and colleagues wrote.

The identification of factors that predict hypocalcemia is necessary to determine which patients may require calcium supplementation therapy and inpatient observation.

The current analysis included 304 patients who underwent total thyroidectomy between Feb. 1, 2010, and Nov. 30, 2012.

Noureldine and colleagues assessed postoperative vitamin D, calcium and intact parathyroid hormone levels within 6 to 8 hours after surgery.

The researchers defined mild hypocalcemia as any postoperative serum calcium level of less than 8.4 mg/dL to 8 mg/dL. They defined significant hypocalcemia as any postoperative serum calcium level less than 8 mg/dL or the development of hypocalcemia-associated symptoms.

Researchers determined mild hypocalcemia occurred in 22.4% of cases and significant hypocalcemia occurred in 29.9% of cases. The majority of patients who developed hypocalcemia were female (P=.003). Postoperative intact parathyroid hormone level was associated with the development of significant hypocalcemia (P<.001).

Multivariable analysis showed males demonstrated a reduced risk for mild (OR=0.37; 95% CI, 0.16-0.85) and significant (OR=0.57; 95% CI, 0.09-0.78) hypocalcemia.

Researchers determined every 10-pg/mL increase in postoperative intact parathyroid hormone level was associated with a 43% reduction in risk for significant hypocalcemia (P<.001) and an 18% reduction in the likelihood of having a hospital stay longer than 24 hours (P=.03).

Patients with a malignant neoplasm demonstrated a 27% increased risk for mild hypocalcemia (P=.02). Additionally, researchers observed a progressively increasing risk for lower levels of intact parathyroid hormone for each parathyroid gland inadvertently resected or auto transplanted. Black race and male gender independently predicted higher intact parathyroid hormone levels.

Disclosure: The researchers report no relevant financial disclosures.  

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