ALB and susceptibility to pneumonia measurement: Comparative analysis confirmed no significant differences (P > 0.05) in all measured covariates, including age, sex, body mass index (BMI), Acute Physiology and Chronic Health Evaluation (APACHE) II score, Glasgow Coma Scale (GCS) score, serum albumin levels, hemoglobin levels, comorbidities, primary disease, mechanical ventilation and pre-enrollment pneumonia status.