Effects of cytokine blocking agents on hospital mortality in patients admitted to ICU with acute respiratory distress syndrome by SARS-CoV2 infection: retrospective cohort study.

Background- The use of cytokine-blocking agents has been proposed to modulate the inflammatory response in patients with COVID19. Tocilizumab and Anakinra were included in the local protocol as an optional treatment in critically ill patients with acute respiratory distress syndrome (ARDS) by SARS-CoV2 infection. This cohort study evaluated the effects of therapy with cytokine blocking agents on in-hospital mortality in COVID19 patients requiring mechanical ventilation and admitted to intensive care unit. Methods- The association between therapy with Tocilizumab or Anakinra and in-hospital mortality was assessed in consecutive adult COVID19 patients admitted to our ICU with moderate to severe ARDS. The association was evaluated by comparing patients who receive to those who did not receive Tocilizumab or Anakinra and by using different multivariable Cox models adjusted for variables related to poor outcome, for the propensity to be treated with Tocilizumab or Anakinra and after patient matching. Results- Sixty-six patients who received immunotherapy (49 Tocilizumab, 17 Anakinra) and 28 patients who did not receive immunotherapy were included. The in-hospital crude mortality was 30,3% in treated patients and 50% in non-treated (OR 0,77, 95% CI 0,56-1,05, p=0,069). The adjusted Cox model showed an association between therapy with immunotherapy and in-hospital mortality (HR 0,40, 95% CI 0,19-0,83, p=0,015). This protective effect was further confirmed in the analysis adjusted for propensity score, in the propensity-matched cohort and in the cohort of patients with invasive mechanical ventilation within 2 hours after ICU admission. Conclusions- Although important limitations, our study showed that cytokine-blocking agents seem to be safe and to improve survival in COVID-19 patients admitted to ICU with ARDS and the need of mechanical ventilation.