HMGB1 and susceptibility to pneumonia measurement: Importantly, we determined that initial appropriate antibiotic use (a clinical factor) and the day 1 HMGB1 concentration (a biomarker) were independent factors for predicting ICU mortality, and the day 1 albumin level was an independent biomarker of predicting 6-month life dependence in relatively healthy patients with severe pneumonia and ARDS status.