Summary: For patients with pneumonia, the 5 item CURB65 and 4 item CRB65 severity scores perform just as well as the much longer and more complicated Pneumonia Severity Index at predicting low, intermediate or high risk of 30-day mortality, but are much simpler to  use; in addition, the CURB65 and CRB65 scores may perform better than the PSI at predicting which patients are at high risk of 30 day mortality.

Strength of Recommendation = A