Determinants of COVID-19 outcomes: A systematic review

  1. Shirley Crankson
  2. Subhash Pokhrel
  3. Nana Kwame Anokye

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Abstract

Background

The current pandemic, COVID-19, caused by a novel coronavirus SARS-CoV-2, has claimed over a million lives worldwide in a year, warranting the need for more research into the wider determinants of COVID-19 outcomes to support evidence-based policies.

Objective

This study aimed to investigate what factors determined the mortality and length of hospitalisation in individuals with COVID-19.

Data Source

This is a systematic review with data from four electronic databases: Scopus, Google Scholar, CINAHL and Web of Science.

Eligibility Criteria

Studies were included in this review if they explored determinants of COVID-19 mortality or length of hospitalisation, were written in the English Language, and had available full-text.

Study appraisal and data synthesis

The authors assessed the quality of the included studies with the Newcastle□Ottawa Scale and the Agency for Healthcare Research and Quality checklist, depending on their study design. Risk of bias in the included studies was assessed with risk of bias assessment tool for non-randomised studies. A narrative synthesis of the evidence was carried out. The review methods were informed by the Joana Briggs Institute guideline for systematic reviews.

Results

The review included 22 studies from nine countries, with participants totalling 239,830. The included studies’ quality was moderate to high. The identified determinants were categorised into demographic, biological, socioeconomic and lifestyle risk factors, based on the Dahlgren and Whitehead determinant of health model. Increasing age (ORs 1.04-20.6, 95%CIs 1.01-22.68) was the common demographic determinant of COVID-19 mortality while living with diabetes (ORs 0.50-3.2, 95%CIs −0.2-0.74) was one of the most common biological determinants of COVID-19 length of hospitalisation.

Review limitation

Meta-analysis was not conducted because of included studies’ heterogeneity.

Conclusion

COVID-19 outcomes are predicted by multiple determinants, with increasing age and living with diabetes being the most common risk factors. Population-level policies that prioritise interventions for the elderly population and the people living with diabetes may help mitigate the outbreak’s impact.

PROSPERO registration number

CRD42021237063.

Strength and limitations of this review

  • This is the first systematic review synthesising the evidence on determinants of COVID-19 LOS outcome.

  • It is also the first review to provide a comprehensive investigation of contextual determinants of COVID-19 outcomes, based on the determinants of health model; thus, presenting with crucial gaps in the literature on the determinants of COVID-19 outcomes that require urgent attention.

  • The review was restricted in conducting meta-analysis due to included studies’ heterogeneity.

  • The review focused on only papers published in the English Language; hence, other relevant papers written on other languages could have been omitted.

Article activity feed

  1. ScreenIT

    SciScore for 10.1101/2021.03.21.21254068: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    RandomizationThe third author (SP) randomly selected and reviewed 50% of the extracted data from the included studies to ascertain data extraction quality.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Search strategy: From 21st to 31st December 2020, Scopus, Google Scholar, CINAHL and Web of Science databases were searched for relevant studies using the search terms: ‘Determinants’ ‘Predictors’ ‘COVID-19’ ‘SARS-CoV-2’ ‘Mortality’ ‘Length of hospital stay’ ‘Length of hospitalisation’.
    Google Scholar
    suggested: (Google Scholar, RRID:SCR_008878)

    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:
    Regarding limitations, the review was restricted in conducting further analysis, specifically, meta-analysis, to precisely estimate the associations’ effect size due to included studies’ heterogeneity. Also, most of the included studies (n=12) used retrospective design, thus, there was the possibility of residual confounders that could influence this review’s findings. Additionally, all of them used secondary data from medical records of participants. Therefore, any omission or data entry error could affect their results and this review. Hence, caution must be taken when interpreting the findings of this review.

    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 10.1101/2021.03.21.21254068v1 on medRxiv