Validity of pneumonia severity assessment scores in low- and middle-income countries: a systematic review and meta-analysis

Abstract Background Community-acquired pneumonia (CAP) treatment decisions are often guided by severity assessment scores, such as pneumonia severity index (PSI) and CURB-65. Although widely used, their validity in low- and middle-income countries (LMICs) is not well-defined. We aimed to investigate the available evidence around the validity and performance of the existing scores in adults with CAP in LMICs. Methods Medline, Embase, Cochrane Central Register of Controlled Trials, Scopus, and Web of Science were searched to May 21, 2020. Studies of any design evaluating a pneumonia severity score/tool among adults in LMICs were included. Bivariate random-effects meta-analysis was performed to examine the scores' performance in predicting mortality when at least four studies were identified. Studies' quality was assessed with Quality in Prognosis Studies criteria. Results Of 9,898 records, 11 studies were eligible covering 12 tools. Of these, only CURB-65 and CRB-65 were included in the meta-analysis. Both scores were effective in predicting mortality risk. Performance characteristics (with 95% Confidence intervals) at high (CURB-65 ≥3, CRB-65 ≥3) and intermediate-risk (CURB-65 ≥2, CRB-65 ≥1) cut-offs, respectively, were as follows: for CURB-65, pooled sensitivity, 0.70 (0.25-0.94) and 0.96 (0.49-1.00), and for CRB-65, 0.09 (0.01-0.48) and 0.93 (0.50-0.99); pooled specificity, for CURB-65, 0.90 (0.73-0.96) and 0.64 (0.45-0.79), and for CRB-65, 0.99 (0.95-1.00) and 0.43 (0.24-0.64). Conclusion CURB-65 and CRB-65 appear to be valid scores for predicting mortality in LMICs. Whilst CURB-65 exhibited better performance in most aspects, CRB-65 may be employed where urea levels are unavailable. Lack of robust evidence regarding other scores, including PSI.