BACKGROUND: The performance of CURB65 in predicting mortality in 
community-acquired pneumonia (CAP) has been tested in two large observational 
studies. However, it has not been tested against generic sepsis and early 
warning scores, which are increasingly being advocated for identification of 
high-risk patients in acute medical wards.
METHOD: A retrospective analysis was performed of data prospectively collected 
for a CAP quality improvement study. The ability to stratify mortality and 
performance characteristics (sensitivity, specificity, positive predictive 
value, negative predictive value and area under the receiver operating curve) 
were calculated for stratifications of CURB65, CRB65, the systemic inflammatory 
response syndrome (SIRS) criteria and the standardised early warning score 
(SEWS).
RESULTS: 419 patients were included in the main analysis with a median age of 74 
years (men = 47%). CURB65 and CRB65 stratified mortality in a more clinically 
useful way and had more favourable operating characteristics than SIRS or SEWS; 
for example, mortality in low-risk patients was 2% when defined by CURB65, but 
9% when defined by SEWS and 11-17% when defined by variations of the SIRS 
criteria. The sensitivity, specificity, positive predictive value and negative 
predictive value of CURB65 was 71%, 69%, 35% and 91%, respectively, compared 
with 62%, 73%, 35% and 89% for the best performing version of SIRS and 52%, 67%, 
27% and 86% for SEWS. CURB65 had the greatest area under the receiver operating 
curve (0.78 v 0.73 for CRB65, 0.68 for SIRS and 0.64 for SEWS).
CONCLUSIONS: CURB65 should not be supplanted by SIRS or SEWS for initial 
prognostic assessment in CAP. Further research to identify better generic 
prognostic tools is required.