ALB and susceptibility to pneumonia measurement: The albumin [Fig. 5G, − 5.17 g/L, 95% CI (− 7.09, − 3.25), P < 0.00001], PaO2/FiO2 [Fig. 5H, − 55.05 mmHg, 95% CI (− 60.11, − 50.00), P < 0.00001], and arterial blood PH [Fig. 5I, − 0.09, 95% CI (− 0.15, − 0.04), P = 0.0005] tended to be lower in severe pneumonia patients who did not survive.