Fig. 2

Variable weighting in the machine-learning models: Survival of Severely Ill COVID (SOSIC) scores on days 1, 7 and 14. A color gradient is used to show variable strength in the machine-learning models at different times, ranging from yellow for the highest preponderance input variables to progressively darker shade of purple for lower input variables. D day, BMI body mass index, ICU intensive care unit, MV mechanical ventilation, SOSIC Survival of Severely Ill COVID score, SOFA Sequential Organ-Failure Assessment, VAP ventilator-associated pneumonia