Friday, 24 September, 2021
HomeCoronavirus WatchCharacterisation of in-hospital complications associated with COVID-19 — UK multicentre study

Characterisation of in-hospital complications associated with COVID-19 — UK multicentre study

A multicentre UK study characterised the extent and effect of COVID-19 complications using the International Severe Acute Respiratory and Emerging Infections Consortium WHO Clinical Characterisation Protocol.

Many people worldwide have been hospitalised with COVID-19 after SARS-CoV-2 infection, and evidence shows these patients have high mortality rates (26%): up to 17% of those admitted to hospital will require ventilatory support and critical care.

Several case reports, cross-sectional studies, and case-control studies have described the presence of non-respiratory complications in those with COVID-19 and suggest that these are likely to be associated with poor outcomes.

A study published in The Lancet explains that a substantial proportion of patients with COVID-19 will develop critical illness and require organ support. Survival after critical illness is often accompanied by a substantial burden of additional physical and mental health morbidity that cannot be measured by mortality outcomes. Mortality has been widely used as an outcome in epidemiological studies and randomised controlled trials for patients with COVID-19 but fails to capture the immediate short-term health issues faced by survivors, including in-hospital complications and functional outcomes.

In patients with COVID-19 undergoing surgery, high rates of post-procedural mortality and complications have been noted, but systematic characterisation of hospitalised patients with COVID-19 is lacking. In other non-SARS-CoV-2 viral illnesses, for example influenza, short-term complications such as myocardial infarction, acute kidney injury, and stroke, are common and can cause greater morbidity than the initial infection itself.

Understanding which patients develop short- term complications might also allow clinicians and researchers to develop care pathways and interventions to mitigate these. As many patients with COVID-19 are critically unwell, identifying the burden of short-term morbidity could help understand the long-term burden on healthcare systems and society for those who survive it.

The study notes that understanding the possible complications of COVID-19 is important for patient management and provision in health-care systems. For patients, information around in-hospital complication rates are important for decision-making about treatment, long-term planning, possible resumption of normal activity and, more recently, vaccination.

For healthcare systems, these data are vital to inform immediate preparedness measures (ie, allocation of resources, equipment, and staffing) and also for long-term planning of health-care delivery to a population that might have incurred additional morbidity due to COVID-19.

Study details

Characterisation of in-hospital complications associated with COVID-19 using the ISARIC WHO Clinical Characterisation Protocol UK: a prospective, multicentre cohort study

Thomas M Drake, Aya M Riad, Cameron J Fairfield, Conor Egan, Stephen R Knight, Riinu Pius, Hayley E Hardwick, Lisa Norman, Catherine A Shaw, Kenneth A McLean, A A Roger Thompson, Antonia Ho, Olivia V Swann, Michael Sullivan, Felipe Soares, Karl A Holden, Laura Merson, Daniel Plotkin, Louise Sigfrid, Thushan I de Silva, Michelle Girvan, Clare Jackson, Clark D Russell, Jake Dunning, Tom Solomon, Gail Carson, Piero Olliaro, Jonathan S Nguyen-Van-Tam, Lance Turtle, Annemarie B Docherty, Peter JM Openshaw, J Kenneth Baillie, Ewen M Harrison, Malcolm G Semple, on behalf of the ISARIC4C investigators

Published in The Lancet 17 July 2021



COVID-19 is a multisystem disease and patients who survive might have in-hospital complications. These complications are likely to have important short-term and long-term consequences for patients, health-care utilisation, health-care system preparedness, and society amid the ongoing COVID-19 pandemic.

Our aim was to characterise the extent and effect of COVID-19 complications, particularly in those who survive, using the International Severe Acute Respiratory and Emerging Infections Consortium WHO Clinical Characterisation Protocol UK.

We did a prospective, multicentre cohort study in 302 UK healthcare facilities. Adult patients aged 19 or older, with confirmed or highly suspected SARS-CoV-2 infection leading to COVID-19, were included in the study. The primary outcome of this study was the incidence of in-hospital complications, defined as organ-specific diagnoses occurring alone or in addition to any hallmarks of COVID-19 illness. We used multilevel logistic regression and survival models to explore associations between these outcomes and in-hospital complications, age, and pre- existing comorbidities.

Between 17 January and 4 August 2020, 80 388 patients were included in the study. Of those admitted to hospital for management of COVID-19, 49.7% (36 367 of 73 197) had at least one complication. The mean age of our cohort was 71.1 years, with 56.0% (41 025 of 73 197) being male and 81.0% (59 289 of 73 197) having at least one comorbidity. Males and those older than 60 were most likely to have a complication (aged ≥60 years: 54.5% [16 579 of 30 416] in males and 48.2% [11 707 of 24 288] in females; aged <60 years: 48.8% [5179 of 10 609] in males and 36.6% [2814 of 7689] in females). Renal (24.3%, 17 752 of 73 197), complex respiratory (18.4%, 13 486 of 73 197), and systemic (16.3%, 11 895 of 73 197) complications were the most frequent. Cardiovascular (12.3%, 8973 of 73 197), neurological (4.3%, 3115 of 73 197), and gastrointestinal or liver (0.8%, 7901 of 73 197) complications were also reported.

Complications and worse functional outcomes in patients admitted to hospital with COVID-19 are high, even in young, previously healthy individuals. Acute complications are associated with reduced ability to self-care at discharge, with neurological complications being associated with the worst functional outcomes. COVID-19 complications are likely to cause a substantial strain on health and social care in the coming years. These data will help in the design and provision of services aimed at the post-hospitalisation care of patients with COVID-19.


The Lancet article – Characterisation of in-hospital complications associated with COVID-19 using the ISARIC WHO Clinical Characterisation Protocol UK: a prospective, multicentre cohort study (Open access)


See more from MedicalBrief archives:


COVID-19 patients with neurological symptoms have 6x higher hospital mortality


Overweight or obese patients risk more severe COVID-19 — 11-country analysis


Increased organ damage after COVID-19 discharge from hospital — UK cohort study


COVID-19 patients can be categorised into three clinical phenotypes


Relationship between COVID-19 deaths and morbid obesity — large US analysis


Subscribe to our Newsletter

Receive Medical Brief's free weekly e-newsletter.

* indicates required