Study of more than 16,700 COVID-19 patients identifies characteristics of severe disease


01-05-2020
illustration of two people in hospital beds

To answer many urgent questions about the characteristics of people who are most severely affected by coronavirus and what happens to them in hospital, a study – called ‘ISARIC4C’ – has analysed data obtained from 16,749 COVID-19 hospital patients in the UK.

The study is led by researchers from the University of Edinburgh, University of Liverpool, and Imperial College London, and was funded by UKRI as part of the UKRI/DHSC/NIHR COVID-19 rapid research response.

To provide real-time information in the pandemic, the results have been published on a preprint site, medRxiv, so it should be noted that the findings have not yet been peer-reviewed and accepted in a journal.

The analysis found that, overall, 49% of the COVID-19 hospital patients were discharged alive, 33% had died and 17% continued to receive care at date of reporting.

Admission to high dependency or intensive care units was required for 17% of patients and of these, 31% were discharged alive, 45% died and 24% continued to receive care at the reporting date. Of those receiving mechanical ventilation, 20% were discharged alive, 53% died and 27% remained in hospital.

The commonest comorbidities were chronic cardiac disease (29%), uncomplicated diabetes (19%), non-asthmatic chronic pulmonary disease (19%) and asthma (14%); however 47% had no documented reported comorbidity.

The researchers have found that after adjusting for other medical problems such as lung, heart and kidney disease that are already known to cause poor outcomes, being male or obese was a significant factor associated with death in UK hospitals, a feature not seen in China, where it is thought that fewer people are obese.

Although the reasons why obese people are suffering such severe COVID-19 and dying more than other groups are not clear, the researchers believe it could be because they have reduced lung function and possibly more inflammation in adipose tissue – the fatty tissue under the skin and around internal organs – which might contribute to an enhanced ‘cytokine storm’ – a potentially life-threatening over-reaction of the body’s immune reaction which causes harm.

The analysis is based on information obtained by over 2,500 research nurses and medical students from 166 UK hospitals. It is the largest study of its kind outside China, where this coronavirus first emerged. The results of the study have already been shared with UK Government and World Health Organisation and are being compared with data from other countries around the world.

The ISARIC4C study is being led by Professor Kenny Baillie at Edinburgh University, Professor Calum Semple at Liverpool University and Professor Peter Openshaw at Imperial College London. The analysis that found the relationship between sex, obesity and poor outcome was done by Dr Annemarie Docherty and Professor Ewen Harrison at Edinburgh University.

Professor Calum Semple, University of Liverpool, said: “One in three people admitted to hospital with of COVID-19 in the UK have contributed to this vital research. The contribution of UK patients in such tragic circumstances been critical to improving the global understanding of this terrible disease. We must do everything humanly possible to understand this disease, so that we are better prepared for the next wave of this pandemic.”

Dr Annemarie Docherty, University of Edinburgh, said: “Hard data cannot convey the human story of individuals and their loved ones who have suffered, changed or sadly passed due to COVID-19. Yet with every contribution to this important study, patients and their carers, with the assistance of dedicated researchers, have struck a blow in the fight to curb this pandemic.”

Professor Peter Openshaw, Imperial College London, said: “This study is quite amazing in that it was launched with such speed and collected so much data. It highlights several crucial questions which researchers, healthcare professionals, the public and patients need answers to. Our research provides an exceptional picture of the illness and risk factors and will underpin a huge range of research. We really appreciate the huge effort that so many people made to send in clinical information and collect samples. It is salutatory to recognise that people risked their lives to collect material for this study. We thank them all as well as the funders, the patients and their relatives, and promise that we will do all we can to find ways to fight the disease.”

Dr Kenneth Baillie, University of Edinburgh, said: “There are some things that the UK does very well – working together is one of them, particularly in healthcare. Gathering this information took tremendous dedication and effort from thousands of research staff across the UK. Together they have created an open resource that will be used by scientists across the world to better understand this new disease.”

The preprint of the paper, titled ‘Features of 16,749 hospitalised UK patients with COVID-19 using the ISARIC WHO Clinical Characterisation Protocol’, can be found on medRxiv.

Based on content by the University of Liverpool.

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