# The prognostic value of serum apolipoprotein A1 levels in elderly patients with de novo SARS-CoV-2 omicron infection

## TL;DR

This study shows that low levels of a protein called ApoA1 in the blood at diagnosis can predict worse outcomes in elderly patients infected with the omicron variant of SARS-CoV-2.

## Contribution

The study identifies serum ApoA1 as an independent prognostic biomarker for omicron infection severity and mortality in elderly patients.

## Key findings

- Low ApoA1 levels at diagnosis correlated with increased mortality in omicron-infected patients.
- Reduced ApoA1 levels were associated with higher CRP and β2-MG levels, indicating greater inflammation.
- ApoA1 levels below 0.87 g/L were an independent predictor of poor prognosis in omicron patients.

## Abstract

The coronavirus disease of 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2, has affected millions of people worldwide. The omicron variant is currently the predominant strain circulating worldwide. Serum apolipoprotein A1 (ApoA1) is linked to endothelial cell injury and serves as a valuable biomarker for monitoring the progression of inflammation in infected individuals. However, the potential roles of ApoA1 in the context of the omicron variant remain elusive.

To investigate the prognostic value of serum ApoA1 levels at diagnosis, using mortality rate as the primary evaluation indicator, we performed a 65-day monitoring and retrospectively analyzed a cohort of 237 individuals diagnosed with omicron. Patients were categorized into two groups based on their ApoA1 levels, high and low. The Kaplan-Meier method was employed to assess overall survival (OS), while the log-rank test was utilized for comparative analysis between the groups. Additionally, both univariate and multivariate Cox proportional hazards models were applied to evaluate the prognostic significance of ApoA1 levels.

Our results indicated that ApoA1 levels were significantly reduced in patients infected with the omicron variant. Notably, ApoA1 levels in severe cases were lower than those in mild-to-moderate cases, with this difference reaching statistical significance. Additionally, we observed a significant increase in C-reactive protein (CRP) and beta-2 microglobulin (β2-MG) levels in individuals with decreased ApoA1 levels. Furthermore, patients with reduced ApoA1 levels exhibited a statistically significant decline in OS (P = 0.001). A decreased ApoA1 level (< 0.87 g/L) was identified as an independent adverse prognostic factor for OS in omicron patients, as determined by multivariate cox proportional hazards regression analysis (P = 0.035).

The serum ApoA1 level at the initial diagnosis was significantly correlated with the severity and prognosis of omicron infections. Therefore, we propose that decreased levels of ApoA1 may serve as an independent negative prognostic factor in patients infected with omicron.