Interleukine-6 in critically ill COVID-19 patients: A retrospective analysis

PLoS One. 2020 Dec 31;15(12):e0244628. doi: 10.1371/journal.pone.0244628. eCollection 2020.

Abstract

Introduction: Coronavirus disease 2019 (COVID-19) appeared in China in December 2019 and has spread around the world. High Interleukin-6 (IL-6) levels in COVID-19 patients suggest that a cytokine storm may play a major role in the pathophysiology and are considered as a relevant parameter in predicting most severe course of disease. The aim of this study was to assess repeated IL-6 levels in critically ill COVID-19 patients admitted to our Intensive Care Unit (ICU) and to evaluate their relationship with patient's severity and outcome.

Methods: We conducted a retrospective study on patients admitted to the ICU with a diagnosis of COVID-19 between March 10 (i.e. the date of the first admitted patients) and April 30, 2020. Demographic, clinical and laboratory data were collected at admission. On the day of IL-6 blood concentration measurement, we also collected results of D-Dimers, C-Reactive Protein, white blood cells and lymphocytes count, lactate dehydrogenase (LDH) and ferritin as well as microbiological samples, whenever present.

Results: Of a total of 65 patients with COVID-19 admitted to our ICU we included 41 patients with repeated measure of IL-6. There was a significant difference in IL-6 levels between survivors and non-survivors over time (p = 0.001); moreover, non survivors had a significantly higher IL-6 maximal value when compared to survivors (720 [349-2116] vs. 336 [195-646] pg/mL, p = 0.01). The IL-6 maximal value had a significant predictive value of ICU mortality (AUROC 0.73 [95% CI 0.57-0.89]; p = 0.01).

Conclusions: Repeated measurements of IL-6 can help clinicians in identifying critically ill COVID-19 patients with the highest risk of poor prognosis.

Publication types

  • Clinical Trial

MeSH terms

  • COVID-19 / blood*
  • COVID-19 / mortality*
  • Critical Illness
  • Cytokine Release Syndrome / blood*
  • Cytokine Release Syndrome / mortality*
  • Disease-Free Survival
  • Female
  • Humans
  • Interleukin-6 / blood*
  • Male
  • Middle Aged
  • Retrospective Studies
  • SARS-CoV-2*
  • Severity of Illness Index
  • Survival Rate

Substances

  • IL6 protein, human
  • Interleukin-6

Grants and funding

The author(s) received no specific funding for this work.