Background: Understanding the risk factors for poor outcomes among COVID-19 patients could help identify vulnerable populations who would need prioritisation in prevention and treatment for COVID-19. We aimed to critically appraise and synthesise published evidence on the risk factors for poor outcomes in hospitalised COVID-19 patients.

Methods: We searched PubMed, medRxiv and the WHO COVID-19 lit-erature database for studies that reported characteristics of COVID-19 patients who required hospitalisation. We included studies published between January and May 2020 that reported adjusted effect size of any demographic and/or clinical factors for any of the three poor outcomes: mortality, intensive care unit (ICU) admission, and invasive mechanical ventilation. We appraised the quality of the included studies using Jo-anna Briggs Institute appraisal tools and quantitatively synthesised the evidence through a series of random-effect meta-analyses. To aid data interpretation, we further developed an interpretation framework that indicated strength of the evidence, informed by both quantity and qual-ity of the evidence.

Results: We included a total of 40 studies in our review. Most of the in-cluded studies (29/40, 73%) were assessed as “good quality”, with as-sessment scores of 80 or more. We found that male sex (pooled odds ratio (OR)=1.32 (95% confidence interval (CI)=1.18-1.48; 20 studies), older age (OR=1.05, 95% CI=1.04-1.07, per one year of age increase; 10 studies), obesity (OR=1.59, 95% CI=1.02-2.48; 4 studies), diabetes (OR=1.25, 95% CI=1.11-1.40; 11 studies) and chronic kidney diseases (6 studies; OR=1.57, 95% CI=1.27-1.93) were associated with increased risks for mortality with the greatest strength of evidence based on our in-terpretation framework. We did not find increased risk of mortality for several factors including chronic obstructive pulmonary diseases (5 stud-ies), cancer (4 studies), or current smoker (5 studies); however, this does not indicate absence of risk due to limited data on each of these factors.

Conclusion: Male sex, older age, obesity, diabetes and chronic kidney diseases are important risk factors of COVID-19 poor outcomes. Our review provides not only an appraisal and synthesis of evidence on the risk factors of COVID-19 poor outcomes, but also a data interpretation framework that could be adopted by relevant future research.


© 2021 by the Journal of Global Health. All rights reserved. This work is licensed under a Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/).

Cite as

Li, Y., Chung, A., Dighero, I., Dozier, M., Horne, M., McSwiggan, E., Shamsuddin, A. & Nair, H. 2021, 'Risk factors for poor outcomes in hospitalised COVID-19 patients: a systematic review and meta-analysis', Journal of Global Health, 11, article no: 10001. https://dx.doi.org/10.7189/jogh.11.10001

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Last updated: 16 June 2022
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