Fig 2. Patient profiles at hospital admission. The left panel shows the dendogram generated using the hierarchical clustering approach. The right panel shows the representation of patients and variables on the first two components of the PCA. COPD : chronic obstructive pulmonary disease , HBP : high blood pressure , Max oxygen : maximum oxygen flow over 24 h of admission , CRP : C-reactive protein , BMI : body mass index; Signs Time : time since disease onset .