Validity of Pneumonia Severity Assessment Scores in Africa and South Asia: A Systematic Review and Meta-Analysis

Background: Although community-acquired pneumonia (CAP) severity assessment scores are widely used, their validity in low- and middle-income countries (LMICs) is not well defined. We aimed to investigate the validity and performance of the existing scores among adults in LMICs (Africa and South Asia). 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). Conclusions: CURB-65 and CRB-65 appear to be valid for predicting mortality in LMICs. CRB-65 may be employed where urea levels are unavailable. There is a lack of robust evidence regarding other scores, including the Pneumonia Severity Index (PSI).