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. 2023 Apr;22(4):382-388.

Interleukin-6 in COVID-19 Severity Stratification

Fernando Pereira da Silva  1   2 , Maria Filomena Luís  1   2 , Filipa Jesus  1 , Joana Ribeiro  1 , Élin Almeida  1 , Sara Braga  1 , Luís Ferreira  1   2
Affiliations

Interleukin-6 in COVID-19 Severity Stratification

Fernando Pereira da Silva et al. Tanaffos. 2023 Apr.

Abstract

Background: The increase in the number of patients with COVID-19 on a global scale made the early recognition of severe forms of the disease essential. Considering that IL-6 acts as a pro-inflammatory mediator, mediating acute phase responses, the objective of this study was to assess its value in the early severity stratification of SARS-CoV2 infection.

Materials and methods: It was a prospective study included IL-6 measurement in patients with SARS-CoV2 infection upon admission to the emergency department. Two groups were considered (Group I: patients without hospitalization criteria; Group II: patients with hospitalization criteria). Analyzed variables were serum levels of IL-6, C-reactive protein, ferritin, d-dimers, sociodemographics, ventilator support, ICU admission, mortality, dates of diagnosis, hospitalization, and discharge. For the statistical analyses, Mann-Whitney test, Pearson's chi-square test, area under the receiver operating characteristic curve, Youden index, and Spearman correlation were applied.

Results: A total number of 117 patients were included. Mean age was significantly higher for group II (72,35±15,39 years; p<0,001). No statistically significant difference was seen between the groups regarding gender (p=0,111). The IL-6 values showed an excellent power of discrimination for the need for hospitalization (AUC=0,888; p<0,001) and the need for ICU admission (AUC=0,897; p=7.9 × 10-5). Also, its cut-off value of 12,4pg/mL for the need for hospitalization and 42,95 pg/mL for the need for ICU admission was determined. Positive correlation was seen between IL-6 value and length of stay [r(35)=0,380; p=0,020]. Three deaths were observed among patients with hospitalization criteria (8,1%).

Conclusion: The value of IL-6 at admission seems to independently influence the probability of hospitalization (general ward or ICU) and its duration.

Keywords: COVID-19; Interleukin-6; SARS-CoV-2.

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Conflict of interest statement

Conflict of Interest It is declared that all authors, after reading and approving the manuscript, agreed with the authorship and authorized its submission and publication. The authors have no conflict of interest to declare.

Figures

Figure 1.
Figure 1.
Mean serum levels of IL-6, CRP, Ferritin and D-dimers at admission
Figure 2.
Figure 2.
Predictive value of serum levels of IL-6, CRP, ferritin and d-dimers regarding the need for hospitalization (ROC curves)
Figure 3.
Figure 3.
Predictive value of serum IL-6 level regarding the need for ICU admission (ROC curve)
See this image and copyright information in PMC

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