Article Text

Original research
Demographic risk factors for COVID-19 infection, severity, ICU admission and death: a meta-analysis of 59 studies
  1. Bart G Pijls1,
  2. Shahab Jolani2,
  3. Anique Atherley3,
  4. Raissa T Derckx4,
  5. Janna I R Dijkstra5,
  6. Gregor H L Franssen6,
  7. Stevie Hendriks7,
  8. Anke Richters8,
  9. Annemarie Venemans-Jellema9,
  10. Saurabh Zalpuri10,
  11. Maurice P Zeegers11
  1. 1Department of Orthopaedics, Leiden University Medical Center, Leiden, The Netherlands
  2. 2Department of Methodology and Statistics, Care and Public Health Research Institute (CAPHRI), Maastricht University, Maastricht, The Netherlands
  3. 3Department of Educational Research and Development, School of Health Professions Education, Maastricht University, Maastricht, The Netherlands
  4. 4Department of General Practice, Care and Public Health Research Institute (CAPHRI), Maastricht University, Maastricht, The Netherlands
  5. 5Amsterdam University Medical Center, location VUmc, Amsterdam, The Netherlands
  6. 6Maastricht University Library, Maastricht University, Maastricht, The Netherlands
  7. 7School of Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, The Netherlands
  8. 8Department of Research and Development, The Netherlands Comprehensive Cancer Organisation, Utrecht, The Netherlands
  9. 9De Onderzoekerij, Leiden, The Netherlands
  10. 10UCB Pharma B.V, Breda, The Netherlands
  11. 11NUTRIM School of Translational Research in Metabolism, Care and Public Health Research Institute (CAPHRI), Maastricht University, Maastricht, The Netherlands
  1. Correspondence to Dr Bart G Pijls; b.g.c.w.pijls{at}


Objective We aimed to describe the associations of age and sex with the risk of COVID-19 in different severity stages ranging from infection to death.

Design Systematic review and meta-analysis.

Data sources PubMed and Embase through 4 May 2020.

Study selection We considered cohort and case–control studies that evaluated differences in age and sex on the risk of COVID-19 infection, disease severity, intensive care unit (ICU) admission and death.

Data extraction and synthesis We screened and included studies using standardised electronic data extraction forms and we pooled data from published studies and data acquired by contacting authors using random effects meta-analysis. We assessed the risk of bias using the Newcastle-Ottawa Scale.

Results We screened 11.550 titles and included 59 studies comprising 36.470 patients in the analyses. The methodological quality of the included papers was high (8.2 out of 9). Men had a higher risk for infection with COVID-19 than women (relative risk (RR) 1.08, 95% CI 1.03 to 1.12). When infected, they also had a higher risk for severe COVID-19 disease (RR 1.18, 95% CI 1.10 to 1.27), a higher need for intensive care (RR 1.38, 95% CI 1.09 to 1.74) and a higher risk of death (RR 1.50, 95% CI 1.18 to 1.91). The analyses also showed that patients aged 70 years and above have a higher infection risk (RR 1.65, 95% CI 1.50 to 1.81), a higher risk for severe COVID-19 disease (RR 2.05, 95% CI 1.27 to 3.32), a higher need for intensive care (RR 2.70, 95% CI 1.59 to 4.60) and a higher risk of death once infected (RR 3.61, 95% CI 2.70 to 4.84) compared with patients younger than 70 years.

Conclusions Meta-analyses on 59 studies comprising 36.470 patients showed that men and patients aged 70 and above have a higher risk for COVID-19 infection, severe disease, ICU admission and death.

PROSPERO registration number CRD42020180085.

  • COVID-19
  • infectious diseases
  • epidemiology

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See:

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

Supplementary materials


  • Contributors MPZ conceived the study. All authors were involved in the study design during weekly meetings. GHLF designed and performed the search strategy. AVJ, RTD and BGP screened the titles and abstracts for eligibility. AR and SZ extracted the data (quantitative data) and AA, SH and JIRD reviewed the study quality (qualitative data). SJ analysed the data. BGP and SJ wrote the first draft. All authors revised this draft for critical content. All authors approved the final manuscript. MPZ, BGP and SJ are the guarantors. All persons listed as authors have contributed to preparing the manuscript. All authors had full access to all the data in the study and had final responsibility for the decision to submit for publication.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Dissemination declaration This review will be disseminated via WHO, direct communication with national centres for disease control, international library organisation and via Google Search engine optimisation provided by Maastricht University.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval For this systematic review and meta-analysis, approval by the ethics committee was not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article or uploaded as supplemental information. The study protocol is available online at the PROSPERO website:

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.