# A PTH Value at 6 Hours Postsurgery Predicts the Diagnosis of Transient and Permanent Hypoparathyroidism

## TL;DR

A PTH level measured 6 hours after thyroid surgery can accurately predict whether a patient will develop temporary or permanent hypoparathyroidism.

## Contribution

The study identifies a specific PTH threshold at 6 hours post-surgery that effectively predicts both transient and permanent hypoparathyroidism.

## Key findings

- A PTH level <10.10 pg/mL at 6 hours postsurgery predicts transient hypoparathyroidism with high accuracy (AUC = 0.991).
- The same PTH threshold also effectively predicts permanent hypoparathyroidism (AUC = 0.961).
- Measuring PTH at 6 hours is more accurate than later calcium measurements for predicting hypocalcemia risk.

## Abstract

PTH+ levels after thyroid surgery are generally used to detect patients at risk of developing postoperative hypoparathyroidism. However, there is still a lack of consensus about the threshold value regarding its evaluation, the definition of gland function recovery, and the classification of hypoparathyroidism as permanent.

PTH levels (determined 6 hours after total thyroidectomy) could be effective for early prediction of the risk of postsurgical hypocalcemia and IV calcium requirements during hospitalization, comparing it with the predictive capacity of serum calcium levels at 24 and 48 hours after surgery. We also aim to study the efficacy of the measurement of PTH levels for the predictive diagnosis of permanent hypoparthyroidism.

Prospective cohort study between September 2021 and November 2023.

A public tertiary care hospital (Jaén, Spain).

We collected data on 105 patients undergoing total thyroidectomy.

PTH levels were measured 6 hours postoperatively. Additionally, corrected calcium levels, adjusted for total protein, were measured at 24 hours and 48 hours postsurgery.

In our study, a PTH value at 6 hours postsurgery <10.10 pg/mL suggests, with high sensitivity and specificity, to be a very effective measure for identifying patients who would develop either transient [area under the curve (AUC) = 0.991, 95% confidence interval (CI) 0.978-1] and permanent hypoparathyroidism (AUC = 0.961, 95% CI 0.952-0.997).

Measuring PTH levels at 6 hours postthyroidectomy is an accurate method for predicting which patients are at risk of developing transient and/or permanent hypoparathyroidism.