# Predictors of Postoperative Hypocalcemia and Hypoparathyroidism Following Thyroidectomy in Hanoi, Vietnam

## TL;DR

This study identifies factors that increase the risk of low blood calcium and parathyroid issues after thyroid surgery in Vietnam.

## Contribution

The study identifies specific predictors of postoperative hypocalcemia and hypoparathyroidism in thyroid cancer patients in Vietnam.

## Key findings

- 27.5% of patients experienced hypocalcemia after thyroidectomy, with higher rates in total thyroidectomy cases.
- Total thyroidectomy, low PTH, and low vitamin D levels were strong predictors of hypocalcemia.
- Hypoparathyroidism was linked to total thyroidectomy and reduced PTH levels.

## Abstract

Hypocalcemia is the most frequent complication of thyroid surgeries. Hypocalcemia is the most common complication following thyroid surgeries and is crucial in managing patients with thyroid cancer.

This study aimed to describe hypocalcemia after thyroidectomy and evaluate the factors associated with postoperative hypocalcemia.

A cross-sectional study was conducted on 91 patients with thyroid cancer at Hanoi Medical University Hospital. Hypocalcemia was defined as serum calcium levels lower than 2.1 mmol/L, measured 24 hours after surgery.

In the postoperative period, 27.5% of the patients exhibited hypocalcemia, with distinct prevalence rates observed between the total thyroidectomy group (47.6%) and the thyroid lobectomy group (10.2%). Concurrently, hypoparathyroidism manifested in 15.4% of the cases. Various factors were identified as contributors to postoperative hypocalcemia, including lymph node metastasis (odds ratio [OR] = 2.6; P < 0.05), total thyroidectomy (OR = 8.0; P < 0.01), diminished parathyroid hormone (PTH) levels (OR = 12.6; P < 0.001), and reduced 25-hydroxyvitamin D3 (25[OH]D3) levels (P < 0.01). Furthermore, multivariate analyses revealed that free thyroxine (FT4) (P = 0.04), 25(OH)D3 (P = 0.037), surgical procedure (P < 0.001), and cancer stage (P < 0.001) independently predicted postoperative hypocalcemia. Notably, our findings underscored a substantial correlation between total thyroidectomy (OR = 21.5, P < 0.001), diminished PTH levels (P < 0.001), and the occurrence of postoperative hypoparathyroidism.

The identification of lymph node metastasis, total thyroid surgery, decreased PTH and 25(OH)D3 levels, and albumin concentration are crucial factors in guiding the surgical team to prevent the onset of hypocalcemia.