Assessment of interleukin-6 role in detecting coronavirus disease 2019 severity, mortality, and its control: A cohort study

Background Elevated serum level of interleukin-6 (IL-6) in patients with coronavirus disease 2019 (COVID-19) may be a result of a cytokine storm and can be an indicator of severe and critical forms of the disease.Therefore, it is crucial to detect and control IL-6 level early in severe acute respiratory syndrome coronavirus-2-infected patients; in addition to that, IL-6 may be a target for drug development. Aim In this study, we aimed to evaluate IL-6 serum levels in severe acute respiratory syndrome coronavirus-2-infected patients with positive PCR result early after diagnosis to detect disease severity and mortality. Study design and methods This prospective study was done on 60 COVID-19-infected patients. Serum IL-6 levels were tested after diagnosis. Tocilizumab was given to 11 patients with severe COVID-19. Results High serum levels of IL-6 had been detected in 95% of patients and in all patients of the critical group. Its levels in the mild group were 1.87 times less than that in the moderate group, whereas 2.85 times less than that in the critical group. IL-6 median levels were 24, 44.85, and 68.4 ng/l for the mild, moderate, and critical groups, respectively. The IL-6 concentration was predictive of severity (with IL-6 cutoff value >56 ng/l) and was predictive of mortality (with a cutoff value >67 ng/l) for COVID-19-infected patients. Tocilizumab cure rate was 30% in critical cases. Conclusion Serum IL-6 is of paramount importance in detecting severity and mortality of COVID-19 disease, whereas therapeutic value of tocilizumab needs confirmation by detailed studies.