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/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.