Serum Interleukin-6 Concentrations and the Severity of COVID-19 Pneumonia: A Retrospective Study at a Single Center in Bengbu City, Anhui Province, China, in January and February 2020.

BACKGROUND At present, the relationships among COVID-19 disease progression, patient prognosis, and immune status are unclear. This single-center retrospective study evaluated the correlation between serum interleukin-6 (IL-6) levels at admission with the severity of COVID-19 pneumonia, as determined by admission to the intensive Care Unit (ICU). MATERIAL AND METHODS Patients admitted to The First Affiliated Hospital of Bengbu Medical College in Bengbu City, Anhui Province, China, in January and February 2020 for COVID-19 pneumonia were enrolled in this study. COVID-19 infection was confirmed by the detection of SARS-CoV-2 nucleic acid in throat swab samples using real-time fluorescent reverse transcription PCR. Serum IL-6 concentrations at admission were measured by ELISA. Correlations between serum IL-6 concentrations and ICU admission due to the development of severe COVID-19 pneumonia were evaluated. RESULTS This study enrolled 68 patients with novel coronavirus pneumonia. IL-6 concentrations were significantly higher in patients with more severe than less severe COVID-19 pneumonia. Eight of 40 patients with severe COVID-19 pneumonia became critically ill and required ICU admission. IL-6 concentrations were significantly higher in patients with severe COVID-19 pneumonia who were than who were not treated in the ICU. The area under the receiver operating characteristic (ROC) curve (AUC) was 0.816 (P<0.01), indicating that IL-6 was prognostic of disease severity in patients with COVID-19 pneumonia. CONCLUSIONS Serum IL-6 concentration is closely associated with the severity of COVID-19. Continuous monitoring of IL-6 has clinical value in evaluating patient condition.