Prediction accuracy of commonly used pneumonia severity scores in Aboriginal patients with severe community-acquired pneumonia - a retrospective study.

AIMS Assess the prediction accuracy of pneumonia severity scores in Aboriginal patients with severe community-acquired pneumonia (SCAP) and identify risk factors for poor prognosis. METHODS Retrospective cohort study examining Aboriginal patients admitted to intensive care unit (ICU) with confirmed SCAP between January 2011 and December 2014. Severity scores were calculated for SMARTCOP, SMARTACOP, CURB65, PSI, IDSA/ATS SCAP (IASCAP) and APACHE II/III scores using medical records. Prediction accuracy of 30-day mortality and requirement for intensive respiratory and/or vasoactive support (IRVS) were assessed using logistic regression and the area under the receiver operating characteristic curve (AUROC). Multivariate analysis was used to test associations between poor prognosis and demographic/clinical variables. RESULTS A total of 203 cases were identified (49% female). Thirty-day mortality was 6.4% (n=13) and 53% (n=107) required IRVS. None of the tested pneumonia severity scores accurately predicted mortality. SMARTCOP and SMARTACOP predicted IRVS requirement with the highest diagnostic accuracy, but only achieved acceptable discrimination (p=<0.001, <0.001; AUROC=0.74, 0.75, respectively). APACHE II/III predicted both mortality (p=0.003, 0.001; AUROC=0.74, 0.73, respectively) and IRVS requirement (p=<0.001, <0.001; AUROC=0.72, 0.73, respectively). Multivariate analysis associated mortality with male gender, cirrhosis, immunosuppression and acidaemia, and IRVS requirement with multi-lobar pneumonia, hypotension and tachypnoea. Multivariate analysis for mortality and IRVS requirement achieved an AUROC of 0.93 and 0.87, respectively. CONCLUSION None of the pneumonia severity scores accurately predicted mortality. We recommend SMARTACOP to predict IRVS requirement in Aboriginal patients with SCAP. Given Aboriginal patients are over-represented in Australian ICUs, a new score is warranted for this understudied population. This article is protected by copyright. All rights reserved.