COVID-19 mortality risk assessment: An international multi-center study

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Abstract

Timely identification of COVID-19 patients at high risk of mortality can significantly improve patient management and resource allocation within hospitals. This study seeks to develop and validate a data-driven personalized mortality risk calculator for hospitalized COVID-19 patients. De-identified data was obtained for 3,927 COVID-19 positive patients from six independent centers, comprising 33 different hospitals. Demographic, clinical, and laboratory variables were collected at hospital admission. The COVID-19 Mortality Risk (CMR) tool was developed using the XGBoost algorithm to predict mortality. Its discrimination performance was subsequently evaluated on three validation cohorts. The derivation cohort of 3,062 patients has an observed mortality rate of 26.84%. Increased age, decreased oxygen saturation (≤ 93%), elevated levels of C-reactive protein (≥ 130 mg/L), blood urea nitrogen (≥ 18 mg/dL), and blood creatinine (≥ 1.2 mg/dL) were identified as primary risk factors, validating clinical findings. The model obtains out-of-sample AUCs of 0.90 (95% CI, 0.87–0.94) on the derivation cohort. In the validation cohorts, the model obtains AUCs of 0.92 (95% CI, 0.88–0.95) on Seville patients, 0.87 (95% CI, 0.84–0.91) on Hellenic COVID-19 Study Group patients, and 0.81 (95% CI, 0.76–0.85) on Hartford Hospital patients. The CMR tool is available as an online application at covidanalytics.io/mortality_calculator and is currently in clinical use. The CMR model leverages machine learning to generate accurate mortality predictions using commonly available clinical features. This is the first risk score trained and validated on a cohort of COVID-19 patients from Europe and the United States.

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  1. SciScore for 10.1101/2020.07.07.20148304: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    NIH rigor criteria are not applicable to paper type.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    The derivation cohort includes the healthcare systems of ASST Cremona (Northern Italy), HM Hospitals (Spain), and Hartford HealthCare affiliate hospitals (United States).
    Hartford HealthCare
    suggested: None
    11 All statistical analysis is conducted using version 3.7 of the Python programming language.
    Python
    suggested: (IPython, RRID:SCR_001658)

    Results from OddPub: Thank you for sharing your data.


    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Limitations: Limited hospital capacity can impose potential biases in the training population. Only severe patients were able to be treated, particularly in Europe, and some hospitals were forced to turn away patients deemed too critically ill during the peak of the virus. Thus, hospital admissions data may exclude patients on both ends of the acuity spectrum. Additionally, the scarcity of hospital resources may have led patients to receive insufficient care, increasing mortality risk due to lack of treatment. While this warrants further investigation, initial validation results suggest that the CMR tool generalizes well to less congested systems in Greece and the United States. The differences related to Hartford Hospital might also be related to the timing of the virus. The virus affected Europe before the US. This provided an opportunity to learn from the experience in Europe, which may have resulted in different or more effective treatment decisions as well as governmental policies in the US. This is an opportunity for further study through validation on additional US cohorts. Our clinical features are limited by the data that was commonly available across all sites in the derivation population. We expect that a more comprehensive set of clinical features such as D-Dimer and IL-6 levels, Body Mass Index, radiographic diagnosis, symptoms, and time elapsed between the disease and treatment onset will yield more accurate results. A broader set of comorbidities, including hyp...

    Results from TrialIdentifier: No clinical trial numbers were referenced.


    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.


    Results from JetFighter: We did not find any issues relating to colormaps.


    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

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