# CT semi-quantitative score used as risk factor for hyponatremia in patients with COVID-19: a cross-sectional study

## TL;DR

This study finds that CT scan scores can predict hyponatremia in COVID-19 patients, suggesting a link between lung severity and sodium levels.

## Contribution

The study introduces the semi-quantitative CT score as a novel risk factor for hyponatremia in COVID-19 patients.

## Key findings

- Patients with hyponatremia had higher CT severity scores, indicating more severe lung lesions.
- Hyponatremia in COVID-19 is linked to lower free triiodothyronine and thyroid stimulating hormone levels.
- CT scores, age, and lab values are significant predictors of hyponatremia in a multivariate model.

## Abstract

Chest computed tomography (CT) is used to determine the severity of COVID-19 pneumonia, and pneumonia is associated with hyponatremia. This study aims to explore the predictive value of the semi-quantitative CT visual score for hyponatremia in patients with COVID-19 to provide a reference for clinical practice.

In this cross-sectional study, 343 patients with RT-PCR confirmed COVID-19, all patients underwent CT, and the severity of lung lesions was scored by radiologists using the semi-quantitative CT visual score. The risk factors of hyponatremia in COVID-19 patients were analyzed and combined with laboratory tests. The thyroid function changes caused by SARS-CoV-2 infection and their interaction with hyponatremia were also analyzed.

In patients with SARS-CoV-2 infection, the total severity score (TSS) of hyponatremia was higher [M(range), 3.5(2.5–5.5) vs 3.0(2.0–4.5) scores, P=0.001], implying that patients with hyponatremia had more severe lung lesions. The risk factors of hyponatremia in the multivariate regression model included age, vomiting, neutrophils, platelet, and total severity score. SARS-CoV-2 infection impacted thyroid function, and patients with hyponatremia showed a lower free triiodothyronine (3.1 ± 0.9 vs 3.7 ± 0.9, P=0.001) and thyroid stimulating hormone level [1.4(0.8–2.4) vs 2.2(1.2–3.4), P=0.038].

Semi-quantitative CT score can be used as a risk factor for hyponatremia in patients with COVID-19. There is a weak positive correlation between serum sodium and free triiodothyronine in patients with SARS-CoV-2 infection.