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Original research
Parenchymal lung abnormalities following hospitalisation for COVID-19 and viral pneumonitis: a systematic review and meta-analysis
  1. Laura Fabbri1,2,
  2. Samuel Moss1,2,
  3. Fasihul A Khan2,
  4. Wenjie Chi3,
  5. Jun Xia3,
  6. Karen Robinson4,
  7. Alan Robert Smyth2,5,
  8. Gisli Jenkins1,2,
  9. Iain Stewart1,2
  1. 1 National Heart & Lung Institute, Imperial College London, London, UK
  2. 2 Nottingham NIHR Biomedical Research Centre, University of Nottingham, Nottingham, UK
  3. 3 Institute of Mental Health, University of Nottingham, Nottingham, UK
  4. 4 Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
  5. 5 Division of Child Health, Obstetrics & Gynaecology, University of Nottingham, Nottingham, UK
  1. Correspondence to Dr Iain Stewart, National Heart & Lung Institute, Imperial College London, London SW3 6LY, UK; iain.stewart{at}


Introduction Persisting respiratory symptoms in COVID-19 survivors may be related to development of pulmonary fibrosis. We assessed the proportion of chest CT scans and pulmonary function tests consistent with parenchymal lung disease in the follow-up of people hospitalised with COVID-19 and viral pneumonitis.

Methods Systematic review and random effects meta-analysis of proportions using studies of adults hospitalised with SARS-CoV-2, SARS-CoV, MERS-CoV or influenza pneumonia and followed up within 12 months. Searches performed in MEDLINE and Embase. Primary outcomes were proportion of radiological sequelae on CT scans; restrictive impairment; impaired gas transfer. Heterogeneity was explored in meta-regression.

Results Ninety-five studies (98.9% observational) were included in qualitative synthesis, 70 were suitable for meta-analysis including 60 SARS-CoV-2 studies with a median follow-up of 3 months. In SARS-CoV-2, the overall estimated proportion of inflammatory sequelae was 50% during follow-up (0.50; 95% CI 0.41 to 0.58; I2=95%), fibrotic sequelae were estimated in 29% (0.29; 95% CI 0.22 to 0.37; I2=94.1%). Follow-up time was significantly associated with estimates of inflammatory sequelae (−0.036; 95% CI −0.068 to –0.004; p=0.029), associations with fibrotic sequelae did not reach significance (−0.021; 95% CI −0.051 to 0.009; p=0.176). Impaired gas transfer was estimated at 38% of lung function tests (0.38 95% CI 0.32 to 0.44; I2=92.1%), which was greater than restrictive impairment (0.17; 95% CI 0.13 to 0.23; I2=92.5%), neither were associated with follow-up time (p=0.207; p=0.864).

Discussion Sequelae consistent with parenchymal lung disease were observed following COVID-19 and other viral pneumonitis. Estimates should be interpreted with caution due to high heterogeneity, differences in study casemix and initial severity.

PROSPERO registration number CRD42020183139.

  • COVID-19
  • imaging/CT MRI etc
  • interstitial fibrosis
  • respiratory infection

Data availability statement

Data sharing not applicable as no datasets generated and/or analysed for this study. Data were obtained from published studies.

This article is made freely available for personal use in accordance with BMJ’s website terms and conditions for the duration of the covid-19 pandemic or until otherwise determined by BMJ. You may use, download and print the article for any lawful, non-commercial purpose (including text and data mining) provided that all copyright notices and trade marks are retained.

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Data availability statement

Data sharing not applicable as no datasets generated and/or analysed for this study. Data were obtained from published studies.

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  • Contributors All authors contributed to either the conception, design, data acquisition, data analysis, or interpretation of the work; all authors contributed to the drafting and revising of the manuscript and all authors gave final approval for publication. IS accepts full responsibility for the work and conduct of the study, had access to the data, and controlled the decision to publish.

  • Funding National Institute for Health Research (NIHR) Professorship (RP-2017-08-ST2-014); Rayne Foundation Fellowship.

  • Competing interests GJ reports NIHR BRC salaries, studentships, professorship (RP-2017-08-ST2-014).

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

  • 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.