COVID-19: An evaluation of predictive scoring systems in South Africa

Abstract

Background| The Coronavirus Disease 2019 (COVID-19) pandemic, caused by SARS-CoV-2, has resulted in more than 700 million cases worldwide. Sepsis and pneumonia severity scores assist in risk assessment of critical outcomes in patients with COVID-19. This allows healthcare workers to triage patients, by using clinical parameters and limited special investigations, thus offering the most appropriate level of care. Methods| A retrospective cohort study of 605 adult patients hospitalised with moderate to severe COVID-19, at a tertiary state hospital in South Africa. Evaluating the utility of the CURB65, NEWS2 and ISARIC-4C Mortality Score, in predicting critical outcomes, using clinical characteristics on admission. Outcomes included in-hospital mortality, invasive mechanical ventilation, and intensive care unit admission (ICU). Performance of severity scores and risk factors was assessed by area under the receiver operator characteristics (AUROC) analysis and logistic regression. Findings |A total of 605 records were used, 129 (21 %) non-survivors, 101 (17 %) ICU admissions and 77 (13 %) requiring invasive ventilation. Greater odds of mortality was associated with moderate and severe risk groups of the CURB65, ISARIC-4C and NEWS2 score. Mortality AUROC curve analysis for the CURB65 score was 0·76 (95 % CI: 0·71–0·8), 0·77 (95 % CI: 0·73–0·81) for the ISARIC-4C and 0·77 (95 % CI: 0·73–0·82) for the NEWS2 score. The CURB65 score had a sensitivity of 86 % with 12·8 % mortality, ISARIC-4C score a sensitivity of 87·6 % with 8 % mortality and NEWS2 score a sensitivity of 92·2 % with 8·6 % mortality. Interpretation |In 605 hospitalised patients with moderate to severe COVID-19, predominantly infected by the ancestral strain, good performance of the NEWS2 and ISARIC-4C score in predicting in-hospital mortality was noted. The CURB65 score had a high mortality rate in its low-risk group suggesting unexplained risk factors, not accounted for in the score, thus limiting its utility in the South African setting.