CRP and chronic obstructive pulmonary disease: After feature selection, the following factors associated with greatest increased risk of critical disease were used in model training: age, gender, total number of comorbidities (which included cardiovascular disease, coronary artery disease, chronic kidney disease, asthma/chronic obstructive pulmonary disease, diabetes mellitus, hypertension, and obesity), BMI, respiratory rate, white blood cell count, lymphocyte percentage, creatinine, lactate dehydrogenase (LDH), troponin I, ferritin, procalcitonin, and C-reactive protein (CRP) (Table 2).