IL6 and pneumonia: In the derivation cohort, the following variables were associated with the mortality of patients admitted to ICU due to COVID-19-related pneumonia in univariate logistic regression analysis: age (RR = 3.495, 95% CI 1.801–6.779), albumin (RR = 22.286, 95% CI 9.319–53.294), D-dimer (RR = 2.111, 95% CI 1.091–4.085), IL-6 at admission to ICU (RR = 6.100, 95% CI 2.857–13.023), and CT score (RR = 2.362, 95% CI 1.120–4.980).