METHODS: Medline, Embase, Cochrane Central Register of Controlled Trials, Scopus and Web of Science were searched to 21 May 2020. Studies evaluating a pneumonia severity score/tool among adults in these countries were included. A bivariate random-effects meta-analysis was performed to examine the scores' performance in predicting mortality.

RESULTS: Of 9900 records, 11 studies were eligible, covering 12 tools. Only CURB-65 (Confusion, Urea, Respiratory Rate, Blood Pressure, Age ≥ 65 years) and CRB-65 (Confusion, Respiratory Rate, Blood Pressure, Age ≥ 65 years) were included in the meta-analysis. Both scores were effective in predicting mortality risk. Performance characteristics (with 95% Confidence Interval (CI)) at high (CURB-65 ≥ 3, CRB-65 ≥ 3) and intermediate-risk (CURB-65 ≥ 2, CRB-65 ≥ 1) cut-offs were as follows: pooled sensitivity, for CURB-65, 0.70 (95% CI = 0.25-0.94) and 0.96 (95% CI = 0.49-1.00), and for CRB-65, 0.09 (95% CI = 0.01-0.48) and 0.93 (95% CI = 0.50-0.99); pooled specificity, for CURB-65, 0.90 (95% CI = 0.73-0.96) and 0.64 (95% CI = 0.45-0.79), and for CRB-65, 0.99 (95% CI = 0.95-1.00) and 0.43 (95% CI = 0.24-0.64).