A risk score based on baseline risk factors for predicting mortality in COVID-19 patients

Abstract

Background

To develop a sensitive and clinically applicable risk assessment tool identifying coronavirus disease 2019 (COVID-19) patients with a high risk of mortality at hospital admission. This model would assist frontline clinicians in optimizing medical treatment with limited resources.

Methods

6415 patients from seven hospitals in Wuhan city were assigned to the training and testing cohorts. A total of 6351 patients from another three hospitals in Wuhan, 2169 patients from outside of Wuhan, and 553 patients from Milan, Italy were assigned to three independent validation cohorts. A total of 64 candidate clinical variables at hospital admission were analyzed by random forest and least absolute shrinkage and selection operator (LASSO) analyses.

Results

Eight factors, namely, Oxygen saturation, blood Urea nitrogen, Respiratory rate, admission before the date the national Maximum number of daily new cases was reached, Age, Procalcitonin, C-reactive protein (CRP), and absolute Neutrophil counts, were identified as having significant associations with mortality in COVID-19 patients. A composite score based on these eight risk factors, termed the OURMAPCN-score, predicted the risk of mortality among the COVID-19 patients, with a C-statistic of 0.92 (95% confidence interval [CI] 0.90–0.93). The hazard ratio for all-cause mortality between patients with OURMAPCN-score >11 compared with those with scores ≤ 11 was 18.18 (95% CI 13.93–23.71; p < .0001). The predictive performance, specificity, and sensitivity of the score were validated in three independent cohorts.

Conclusions

The OURMAPCN score is a risk assessment tool to determine the mortality rate in COVID-19 patients based on a limited number of baseline parameters. This tool can assist physicians in optimizing the clinical management of COVID-19 patients with limited hospital resources.

Keywords:

• COVID-19
• risk score
• modeling
• mortality
• in-hospital

Transparency

Declaration of funding

This work was supported by grants from the Special Foundation for Emergency Research on Prevention and Control of COVID-19 of Guangdong Province (2020B1111330003), National Key R&D Program of China (2016YFF0101504, 2019YFC2004700, 2020YFC0845500), the National Science Foundation of China (81630011, 81970364, 81970070, 81970011, 81870171, and 81570412), the Hubei Science and Technology Support Project (2019BFC582, 2018BEC473, and 2017BEC001), Medical flight plan of Wuhan University, and COVID-19 funds of Lombardia Region, CARIPLO and Fondazione Umberto Veronesi to GC.

Declaration of financial/other relationships

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

ZC, JC, JZ, and FL designed study, collected and analyzed data, and wrote manuscript. FZ, PZ, JJQ, LHZ, YML, HTW, MMC, YCZ, LJS, XHS, XYZ, JZ, CZY, WFL, YQY, MYL, WMM, LML, PY, BX, PCL, ZXZ, ZGL, JHW, HFL, XGX, DHW, XFL, GP, LL, JY, GHC, BHZ, XDH and YFY collected and reviewed clinical, laboratory, and radiological data. JC, YML performed statistical analysis. JX, XW, JX, XZ, ZGS and DLG reviewed, interpreted, and checked clinical data. JC, ZGS, PZ and XJZ wrote manuscript and provided valuable suggestions for study design and data analysis. MC, EA, AA, GGS and GC collected, reviewed and analyzed clinical data in Italy and provided valuable suggestions for study design. JG, YBW, PZ, and H.L. contributed equally, designed the project, edited manuscript, and supervised the study. All authors have approved the final version of this paper.

Acknowledgements

None reported.

Data availability statement

The raw data supporting the findings of this study will be available from the corresponding authors after publication. The research team will provide an email address for communication once the data are approved to be shared with others. The proposal with detailed aims, statistical plan, and other information/materials might be required to guarantee the rationality of requirement and the security of data. The data without patient name and identifiers could be shared after reviewing and approving proposal and related materials.

Ethical approval

Studies in all cohorts were approved by the appropriate institutional review boards. Patient informed consent was waived by the ethics committees from each hospital.

Code availability

Codes will be available upon request to the corresponding author after publication.

Transparency statement

The corresponding author affirms that the manuscript is an honest, accurate, and transparent account of the study being reported. No important aspects of the study have been omitted, and all discrepancies from the study as planned have been explained.