Fig. 1

ROC curve analysis of ability of pneumonia severity scores to predict 30-day mortality in cases of community acquired pneumonia (CAP), excluding healthcare-associated pneumonia (HCAP). The AUCs of PSI, IDSA/ATS severe pneumonia criteria, CURB-65 and A-DROP were 0.759 (95% CI: 0.721–0.796), 0.746 (95% CI: 0.707–0.784), 0.754 (95% CI: 0.713–0.794) and 0.764 (95% CI: 0.726–0.802), respectively. In comparisons of the AUCs of these four pneumonia severity scores with each other, the P value was 1.0 in all comparison groups adjusted by the Bonferroni method (PSI vs. IDSA/ATS severe pneumonia criteria, PSI vs. CURB-65, PSI vs. A-DROP, IDSA/ATS severe pneumonia criteria vs. CURB-65, IDSA/ATS severe pneumonia criteria vs. A-DROP, and CURB-65 vs. A-DROP). A-DROP, age ≥70 years in men or age ≥75 years in women, blood urea nitrogen ≥21 mg · dL⁻¹ or dehydration, oxyhemoglobin saturation measured by pulse oximetry ≤90% or partial pressure of oxygen in arterial blood ≤60 Torr, confusion, or systolic blood pressure ≤90 mmHg; ATS, American Thoracic Society; AUC, Area under the curve; CURB-65: confusion, urea >7 mmol/L, respiratory rate ≥30 breaths/min, low blood pressure (systolic <90 mmHg or diastolic ≤60 mmHg), and age ≥65 years; IDSA, Infectious Diseases Society of America; PSI, Pneumonia Severity Index; ROC, Receiver Operating Characteristic