Serum interleukin-6 is an indicator for severity in 901 patients with SARS-CoV-2 infection: a cohort study

• Published in: Journal of translational medicine Vol. 18; no. 1; pp. 406 - 8
• Main Authors: Zhang, Jing, Hao, Yiqun, Ou, Wuling, Ming, Fei, Liang, Gai, Qian, Yu, Cai, Qian, Dong, Shuang, Hu, Sheng, Wang, Weida, Wei, Shaozhong
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 29.10.2020; BioMed Central; BMC
• Subjects: Aged; Antibodies, Monoclonal, Humanized - administration & dosage; Betacoronavirus; Cardiovascular disease; Clinical trials; Cohort analysis; Comorbidity; Coronavirus Infections - blood; Coronavirus Infections - drug therapy; Coronaviruses; COVID-19; COVID-19 Drug Treatment; Cytokines; Diagnosis; Fatalities; Female; Health aspects; Hospitals; Humans; Immunologic tests; Immunosuppressive agents; Infections; Intensive care; Interleukin 6; Interleukin 6 receptors; Interleukin-6 - blood; Kinetics; Laboratories; Male; Medical imaging; Medical prognosis; Middle Aged; Monoclonal antibodies; Oxygen therapy; Pandemics; Patients; Pneumonia, Viral - blood; Pneumonia, Viral - drug therapy; Propensity Score; Retrospective Studies; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Software; Tocilizumab; Treatment Outcome; Ventilators; China; United States > US; COVID-19; SARS-CoV-2; Tocilizumab; Interleukin-6
• ISSN: 1479-5876; 1479-5876
• DOI: 10.1186/s12967-020-02571-x

Interleukin-6 (IL-6) was proposed to be associated with the severity of coronavirus disease 2019 (COVID-19). The present study aimed to explore the kinetics of IL-6 levels, validate this association in COVID-19 patients, and report preliminary data on the efficacy of IL-6 receptor blockade. We conducted a retrospective single-institutional study of 901 consecutive confirmed cases. Serum IL-6 concentrations were tested on admission and/or during hospital stay. Tocilizumab was given to 16 patients with elevated IL-6 concentration. 366 patients were defined as common cases, 411 patients as severe, and 124 patients as critical according to the Chinese guideline on diagnosis and treatment of COVID-19. The median concentration of IL-6 was < 1.5 pg/ml (IQR < 1.50-2.15), 1.85 pg/ml (IQR < 1.50-5.21), and 21.55 pg/ml (IQR 6.47-94.66) for the common, severe, and critical groups respectively (P < 0.001). The follow-up kinetics revealed serum IL-6 remained high in critical patients even when cured. An IL-6 concentration higher than 37.65 pg/ml was predictive of in-hospital death (AUC 0.97 [95% CI 0.95-0.99], P < 0.001) with a sensitivity of 91.7% and a specificity of 95.7%. In the 16 patients who received tocilizumab, IL-6 concentrations were significantly increased after administration, and survival outcome was not significantly different from that of propensity-score matched counterparts (n = 53, P = 0.12). Serum IL-6 should be included in diagnostic work-up to stratify disease severity, but the benefit of tocilizumab needs further confirmation. Trial registration retrospectively registered.