Increased inflammatory mediators levels are associated with clinical outcomes and prolonged illness in severe COVID-19 patients.

ABSTRACT

OBJECTIVE: The purpose of this study was to identify potential predictors of clinical outcome in severe COVID-19 patients and to investigate the relationship between immunological parameters and duration of illness. METHODS: This single-center study retrospectively recruited 73 patients with severe or critical COVID-19. Immunological indicators include white blood cell count, neutrophil count, lymphocyte count, neutrophil-to-lymphocyte ratio, and circulating inflammatory mediators were observed for their association with disease severity, mortality and duration of illness of COVID-19. RESULTS: Serum inflammatory mediators levels of C-reactive protein (P = 0.015), interleukin 6 (IL-6) (P < 0.001), CX3CL1 (P < 0.001), D-dimer (P < 0.001) and procalcitonin (PCT) (P < 0.001) were increased in critical illness patients compared to those severe COVID-19 patients. CX3CL1 has the highest C-index (0.75) to predict in-hospital mortality in patients with COVID-19. Furthermore, this study shows for the first time that the duration of illness in severe COVID-19 patients is associated with serum levels of CX3CL1 (P = 0.037) and D-dimer (P = 0.014). CONCLUSION: CX3CL1, D-dimer, PCT, and IL-6 could effectively predict mortality in severe COVID-19 patients. In addition, only the circulating levels of CX3CL1 and D-dimer were significantly associated with duration of illness.