Fig. 2

Mortality predictive index based on six underlying health factors had a higher AUROC curve compared with CURB65 and PSI. The AUROC curve of six underlying health factors was significantly higher than that of CURB65 (p = 0.02) and was marginally higher than that of PSI (p = 0.05). CURB65 age ≥ 65 years, Confusion, blood Urea nitrogen ≥7 mmol/L, Respiratory rate > 30 per minute, and Blood pressure < 90 mmHg in systole or ≤ 60 mmHg in diastole, PSI Pneumonia Severity Index, AUROC area under the receiver operating characteristic, CI confidence interval. Six underlying health conditions: age ≥ 85 years, hospitalization ≥2 days in the preceding 90 days, home care (wound care or infusion therapy at home), male gender, neoplastic disease, body mass index < 18.5