A third of patients in hospital with COVID-19 may be dying, according to preliminary UK research.
The preprint also found that being male or obese reduced chances of survival from the disease.
More than half of patients mechanically ventilated are dying, the authors said.
The prospective observational cohort study, which has not been peer reviewed, was carried out by a consortium of researchers, known as ISARIC4C, and was led by the University of Liverpool, University of Edinburgh, and Imperial College London (ICL).
They set out to discover who was most severely affected by the virus, what happens to them in hospital, and why some people have better outcomes than others.
A pre-approved questionnaire adopted by the World Health Organisation was used to gather information in 166 UK hospitals between 6th February and 18th April 2020.
A total of 16,749 people with COVID-19, with a median age of 72, were involved in the research.
Main Findings
Overall, the findings showed that:
- 49% of patients were discharged alive
- 33% had died
- 17% continued to receive care at the date of reporting
Of the 17% of patients admitted to High Dependency or Intensive Care Units because of COVID-19:
- 31% were discharged alive
- 45% died
- 24% continued to receive care at the reporting date
Of patients requiring mechanical ventilation:
- 20% were discharged alive
- 53% died
- 27% remained in hospital
The study also cast light on the role that age and sex might play in patient outcomes.
More men (60.2%) than women (39.8%) had been admitted to hospital with COVID-19.
Only 2.0% of patients admitted to hospital were under 18 years.
Six percent of women of reproductive age were pregnant.
Increased age was a strong predictor of in-hospital mortality.
The Role of Obesity
The research found that after adjusting for other medical problems already known to cause poor outcomes, being obese was a significant factor associated with hospital deaths.
Obesity was recognised as a risk factor in 2009 for pandemic A/H1N1 influenza, the authors write, although not in 2016 Middle East respiratory syndrome coronavirus (MERS-CoV).
They speculate that obese people with COVID-19 could have reduced lung function and possibly more inflammation in adipose tissue, which might contribute to an enhanced 'cytokine storm'.
Comorbidities
According to the Department of Health and Social Care, COVID-19 can be more severe in older people and those with chronic heart, lung, and kidney disease, a weakened immune system, diabetes, and some cancers.
The study found that the commonest comorbidities among patients were:
- Chronic cardiac disease (29%)
- Uncomplicated diabetes (19%)
- Non-asthmatic chronic pulmonary disease (19%)
- Asthma (14%)
However, 47% of patients had no documented comorbidity.
Symptoms
The main symptoms found among patients with COVID-19 were:
- Respiratory (cough, sputum, sore throat, runny nose, wheeze, and chest pain)
- Systemic (fever, myalgia, joint pain and fatigue)
- Enteric (abdominal pain, vomiting and diarrhoea)
Out of 11,326 patients, the most common symptoms were cough (70%), fever (69%), and shortness of breath (65%). Fatigue and confusion also featured quite prominently.
Only 4% of patients reported no symptoms.
Professor Calum Semple, from the University of Liverpool, who led the study, said: "We must do everything humanly possible to understand this disease, so that we are better prepared for the next wave of this pandemic."
Professor Peter Openshaw, from the National Heart & Lung Institute at ICL, said: "Our research provides an exceptional picture of the illness and risk factors and will underpin a huge range of research."
'Helpful Insights'
Derek Hill, professor of medical imaging at University College London, described the research as "extremely impressive".
He told the Science Media Centre: "This is an especially large study so it provides helpful insights into the symptoms of COVID-19 patients admitted to hospital.
"As has been reported many times, this is not like flu in who gets seriously ill or in mortality: young children seem to have low risk and pregnant women do not have a increased risk of serious illness, and it is deadlier than flu.
"There are several distinctive clusters of symptoms, with a significant number of patients not having the characteristic cough and fever symptoms. If extrapolated to the community this might suggest some deaths due to COVID-19 might be missed in untested people.
"This work also highlights the link between obesity and poor outcome from COVID-19."
Prof Hill pointed out that the findings only cover people with COVID-19 who were admitted to hospital.
Also, many people are still undergoing treatment, and so mortality and survival figures might change.
Features of 16,749 hospitalised UK patients with COVID-19 using the ISARIC WHO Clinical Characterisation Protocol, doi: https://doi.org/10.1101/2020.04.23.20076042 Paper
