Table 3

Comparative validation of CURB-65 and pneumonia severity index (PSI) in three age groups of patients

Score performance indicatorsWhole cohort (n=987)Younger adults (n=348)Elderly (n=438)Very old (n=201)
PSIArea under ROC curve (95% CI)0.83 (0.78 to 0.87)0.87 (0.77 to 0.97)0.85 (0.80 to 0.90)0.69 (0.60 to 0.79)
Sensitivity, specificity under recommended cut-off pointIV (95.6%, 51.3%)IV (88.9%, 80.6%)IV (100%, 38.3%)IV (100%, 19.8%)
Sensitivity, specificity under adjusted cut-off pointV (72.1%, 80.7%)IV (83.3%, 82.4%)V (83.9%, 79.6%)V (68.4%, 59.3%)
PPV, NPV under recommended cut-off pointIV (21.7%, 97.5%)IV (33.3%, 97.5%)IV (23.9%, 98.5%)IV (14.9%, 94.7%)
PPV, NPV under adjusted cut-off pointV (12.5%, 99.6%)IV (33.3%, 97.5%)IV (23.9%, 98.5%)V (11.5%, 100%)
CURB-65Area under ROC curve (95% CI)0.73 (0.67 to 0.79)0.80 (0.67 to 0.93)0.73 (0.65 to 0.82)0.60 (0.48 to 0.73)
Sensitivity, specificity under recommended cut-off point3 (81.9%, 48.5%)3 (22.2%, 99.7%)3 (64.5%, 74.7%)3 (47.4%, 65.9%)
Sensitivity, specificity under adjusted cut-off point2 (83.8%, 52.3%)2 (61.1%, 95.8%)3 (64.5%, 74.7%)3 (47.4%, 65.9%)
PPV, NPV under recommended cut-off point3 (16.6%, 95.6%)3 (80.0%, 95.9%)3 (16.3%, 96.5%)3 (12.7%, 92.3%)
PPV, NPV under adjusted cut-off point2 (11.5%, 97.8%)2 (44.0%, 97.8%)3 (16.3%, 96.5%)3 (12.7%, 92.3%)
  • NPV, negative predictive value; PPV, positive predictive value.