Background It is not clear whether low-blood pressure criterion could be removed from CURB-65 (confusion, urea >7 mmol/L, respiratory rate ≥30/min, low blood pressure and age ≥65 years) score to orchestrate an improvement in identifying patients with community-acquired pneumonia (CAP) in low–mortality rate settings. Methods A retrospective cohort study of 1,230 CAP patients was performed to simplify the CURB-65 scoring system by excluding low-blood pressure variable. The simplification was validated in a prospective 2-center cohort of 1,409 adults with CAP. Results The hospital mortalities were 1.3% and 3.8% in the retrospective and prospective cohorts, respectively. The mortality rates in the 2 cohorts increased directly with the increasing scores, showing significant increased odds ratios for mortality. The pattern of sensitivity, specificity, positive predictive value and Youden's index of a CUR-65 (Confusion, Urea >7 mmol/L, Respiratory rate ≥30/min and age ≥65 years) score of ≥2 for prediction of mortality was better than that of a CURB-65 score of ≥3 in the retrospective cohort. Higher values of corresponding indices were confirmed in the validation cohort. The higher accuracy of CUR-65 score for predicting mortality was illustrated by the area under the receiver operating characteristic curve of 0.937, compared with 0.915 for CURB-65 score in the retrospective cohort ( P = 0.0073). The validation cohort confirmed a similar paradigm (0.953 versus 0.907, P = 0.0002). Conclusions CURB-65 score could be simplified by removing low blood pressure to orchestrate an improvement in predicting mortality in CAP patients who have a low risk of death. A CUR-65 score of ≥2 might be a more valuable cutoff value for severe CAP.
