ALB and pneumonia: To date, many studies have reported various prognostic factors for CAP, including the pneumonia severity index (PSI) [12–16], PCT [6, 17–26], albumin [27–30], body mass index (BMI) [27, 31], and brain natriuretic peptide (BNP) or N-terminal-proBNP (NT-proBNP) [32, 33].