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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.

People discharged from hospital after being treated for COVID-19 have increased rates of organ damage, readmission and death, compared to the general population. New research suggests that COVID-19 might place a greater burden on healthcare systems than was previously thought.

COVID-19 is known to affect the respiratory system. Increasing evidence suggests it also affects other organs, such as the kidneys, liver and heart. But before this study, it was unclear how many people experience organ damage. 

This study looked at the extra long-term burden on healthcare systems caused by COVID-19. Researchers analysed data on people who had been treated for COVID-19 in hospital. Their health was compared to people in the general population of the same age and with similar medical history.

More than 1 in 10 people treated in hospital for COVID-19 died after they were discharged, the study found. Nearly 1 in 3 were readmitted. They were more likely to develop respiratory disease, cardiovascular disease and diabetes than people in the general population.

More research is needed to understand which groups of people are most likely to develop these complications, the researchers say.

They suggest that an integrated care is needed to diagnose, treat and prevent organ damage after COVID-19. This approach means that the same medical team provides care at all stages of a patient's illness, in hospital and in the community.

Further information on long COVID is available on the NHS website.

What’s the issue?

COVID-19 is known to cause respiratory symptoms and damage the lungs. There is increasing evidence that the disease can also affect the heart, kidney, liver and other organs.

Medical professionals and the public are now aware of long COVID (post COVID syndrome) in which unexplained signs and symptoms continue for 12 weeks or more after infection. However, few studies on long COVID have looked at organ damage beyond the lungs (multiorgan dysfunction). This study set out to address the gap in knowledge.

What’s new?

Researchers looked at the medical records of almost 50,000 people who were hospitalised in England with COVID-19, and discharged. Each was matched to somebody who had not been infected with COVID-19. These controls were the same age, sex and ethnicity, and had a similar medical history. 

The research team gathered information on hospital admission or readmission, and death from any cause. They looked at new diagnoses of respiratory, cardiovascular, metabolic, kidney and liver diseases. The data covered 140 days on average for each patient. 

The researchers found that, compared to matched controls, COVID-19 patients: 

    • were 4 times more likely to be admitted to hospital; nearly 1 in 3 were readmitted (after the initial discharge)
    • were 8 times more likely to die; more than 1 in 10 died
    • were 27 times more likely to have a new diagnosis of a respiratory disease
    • were 3 times more likely to have a new diagnosis of diabetes
    • had a higher risk (50% higher) of a new diagnosis of heart disease.

The increased risk of diabetes and heart disease supports other evidence that COVID-19 damages many organs, not just the lungs.

People who were under 70 or from ethnic minority groups were badly affected after hospital treatment for COVID-19. They were compared, respectively, to the over 70s or to White people in the general population. The under 70s and people from ethnic minority groups had greater increases in risk of death, hospital admission and disease beyond the lungs. 

Why is this important?

In this study, people discharged from hospital after COVID-19 had higher rates of organ damage than similar individuals in the general population. The authors say the diagnosis, treatment and prevention of long COVID therefore needs to be more holistic. It should not focus on a specific organ or symptom. 

The researchers suggest that healthcare professionals look to good examples of integrated care pathways to guide the management of long COVID in future. For instance, clinicians in London and Hertfordshire developed a model for treating the long term lung condition, chronic obstructive pulmonary disease (COPD). The same medical team provides care at all stages of the patient's condition. They found that it improved continuity of care and effective communication between professionals and patients. Compared to standard care, it reduced hospital stays and readmission rates. 

There have been more than 8 million confirmed cases of COVID-19 in the UK. Many more had COVID-19 without being admitted to hospital. Some who had less severe infection also experience long COVID. Organ damage is only part of the problem; many people have other ongoing problems. These include loss of taste and smell, and severe fatigue, which can be debilitating. 

This study suggests that the long-term burden of COVID-19 infection could be substantial for healthcare systems. It adds to the challenge of addressing inequalities in health and providing high quality care for people with long-term conditions.

What’s next?

The study suggests that people hospitalised with COVID-19 have an increased risk of readmission and death. They are more likely to have damage to the lungs and other organs. These increased risks do not just affect older people. 

Better understanding of the risk factors for long COVID could lead to improved treatments and prevention efforts for those with an increased risk of organ damage after being hospitalised with coronavirus. 

The study prompted further research which is ongoing at the University of Cambridge. A clinical trial called HEAL-COVID is also studying people discharged from hospital after COVID-19. They will receive either apixaban (which prevents blood clots), or atorvastatin (which lowers bad cholesterol). Researchers want to see whether either of these treatments reduce the risk of hospital readmission, cardiovascular disease, or death. 

You may be interested to read

This NIHR Alert is based on: Ayoubkhani D, and others. Post-COVID syndrome in individuals admitted to hospital with covid-19: retrospective cohort study. BMJ 2021;372:n693

A linked editorial about the burden of long COVID: Sivan M, and others. Fresh evidence of the scale and scope of long COVID. BMJ 2021;373:n853

Information on HEAL-COVID, the clinical trial aiming to identify beneficial treatments for people discharged from hospital after recovering from COVID-19.


Funding: The study received no external funding. 

Conflicts of Interest: One of the authors has received funding unrelated to this study from AstraZeneca.

Disclaimer: NIHR Alerts are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that views expressed in NIHR Alerts are those of the author(s) and reviewer(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.

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