Risk factors for outcomes of COVID-19 patients: an observational study of 795 572 patients in Russia

  1. A.E. Demkina
  2. S.P. Morozov
  3. A.V. Vladzymyrskyy
  4. V.G. Kljashtorny
  5. O.I. Guseva
  6. P.S. Pugachev
  7. O.R. Artemova
  8. R.V. Reshetnikov
  9. V.A. Gombolevskiy
  10. M.N. Ryabinina

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Abstract

Background

Several factors that could affect survival and clinical outcomes of COVID-19 patients require larger studies and closer attention.

Objective

To investigate the impact of factors including whether COVID-19 was clinically or laboratory-diagnosed, influenza vaccination, former or current tuberculosis, HIV, and other comorbidities on the hospitalized patients’ outcomes.

Design

Observational nationwide cohort study.

Patients

All subjects, regardless of age, admitted to 4,251 Russian hospitals indexed in the Federal Register of COVID-19 patients between March 26, 2020, and June 3, 2020. All included patients for which complete clinical data were available were divided into two cohorts, with laboratory- and clinically verified COVID-19.

Measurements

We analyzed patients’ age and sex, COVID-19 ICD-10 code, the length of the hospital stay, and whether they required ICU treatment or invasive mechanical ventilation. The other variables for analysis were: verified diagnosis of pulmonary disease, cardiovascular disease, diseases of the endocrine system, cancer/malignancy, HIV, tuberculosis, and the data on influenza vaccination in the previous six months.

Results

This study enrolled 705,572 COVID-19 patients aged from 0 to 121 years, 50.4% females. 164,195 patients were excluded due to no confirmed COVID-19 (n=143,357) or insufficient and invalid clinical data (n=20,831). 541,377 participants were included in the study, 413,950 (76.5%) of them had laboratory-verified COVID-19, and 127,427 patients (23.5%) with the clinical verification. Influenza vaccination reduced the risk of transfer to the ICU (OR 0.76), mechanical ventilation requirement (OR 0.74), and the risk of death (HR 0.77). TB increased the mortality risk (HR 1.74) but reduced the likelihood of transfer to the ICU (OR 0.27). HIV comorbidity significantly increased the risks of transfer to the ICU (OR 2.46) and death (HR 1.60). Patients with the clinically verified COVID-19 had a shorter duration of hospital stay (HR 1.45) but a higher risk of mortality (HR 1.08) and the likelihood of being ventilated (OR 1.36). According to the previously published data, age, male sex, endocrine disorders, and cardiovascular diseases increased the length of hospital stay, the risk of death, and transfer to the ICU.

Limitations

The study did not include a control group of subjects with no COVID-19. Because of that, some of the identified factors could not be specific for COVID-19.

Conclusions

Influenza vaccination could reduce the severity of the hospitalized patients’ clinical outcomes, including mortality, regardless of age, social, and economic group. The other factors considered in the study did not reduce the assessed risks, but we observed several non-trivial associations that may optimize the management of COVID-19 patients.

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  1. ScreenIT

    SciScore for 10.1101/2020.11.02.20224253: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIRB: Study design and data sources: The study was approved by the Independent Ethics Committee of Moscow Regional Office of the Russian Society of Radiologists.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    One of our study’s limitations is that the COVID-19 Register does not contain the data on pulmonary disease codes. We believe that a detailed large-scale study is needed to address the effect of pulmonary disease’ type on the severity and outcomes of COVID-19. The other limitation of our study is that the control group of subjects without COVID-19 was absent. Due to that, some of the factors that we have identified could not be specific for COVID-19. Despite the limitations, our findings highlight several previously overlooked factors that could reduce the severity of outcomes and mortality and provide aid for the management of COVID-19 patients.

    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.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  2. Version published to 10.1101/2020.11.02.20224253v1 on medRxiv