IL-6 and Other Biomarkers associated with Poor Prognosis in a Cohort of Hospitalized Patients with COVID-19 in Madrid

OBJECTIVES: There are several published works on the prognostic value of biomarkers in relation to the severity or fatal outcome of coronavirus disease 2019 (COVID-19). In Spain, the second European country in incidence of the disease at the time of data collection, there are few studies that include both laboratory parameters and clinical parameters. Our aim is to study the relationship of a wide series of biomarkers with admission to intensive care and death in a hospital in the Autonomous Community of Madrid (Spain), with special attention to IL-6 due to its role in the systemic inflammatory response associated with a worse prognosis of the disease. METHODS: Data were collected from 546 hospitalized patients with COVID-19. All of them had IL-6 results, in addition to other biochemical and haematological parameters. The difference of the medians for the selected parameters between the groups (ICU vs non-ICU, dead vs survivors) was studied using a Mann-Whitney analysis. The independent variables that predicted death were studied using a Cox proportional hazard regression model. RESULTS: Higher age and blood concentrations of ALT, creatinine, CK, cTnI, LDH, NT-proBNP, CRP, IL-6, leucocyte count and D-dimer together with lower blood concentrations of albumin and lymphocyte count were associated with mortality in univariate analysis. Age, LDH, IL-6 and lymphocyte count remained associated with death in multivariate analysis. CONCLUSIONS: Age, LDH, IL-6 and lymphocyte count, as independent predictors of death, could be used to establish more aggressive therapies in COVID-19 patients.