Half of the coronavirus patients admitted to hospital during the first wave developed at least one complication, new research has found.
The study included more than 70,000 adults in the UK admitted to hospital with severe Covid-19 disease.
Of these, half (36,367 of 73,197) developed one or more health complications during their stay.
Kidney injury was the most common complication (24.3%), followed by lung complications (18.4%) and heart complications (12.3%).
Those with complications were nearly twice as likely to die and seven times more likely to need intensive care when compared to people without complications, the study found.
Complications in patients admitted to hospital were high, even in young, previously healthy individuals.
Researchers say these complications are likely to have important short and long-term impacts for patients, healthcare utilisation, healthcare system preparedness and society amid the ongoing pandemic.
They also note these complications are different to long Covid symptoms in patients who were not admitted to hospital with the disease.
This work contradicts current narratives that Covid-19 is only dangerous in people with existing comorbidities and the elderlyProfessor Calum Semple
According to the study, 27% of 19 to 29-year-olds and 37% of 30 to 39-year-olds experienced a complication.
Acute complications were associated with reduced ability self-care discharge – with 13% of 19 to 29-year-olds and 17% of 30 to 39-year-olds unable to look after themselves once discharged from hospital.
The study looked at cases between January 17 and August 4 last year before vaccines were widely available, and new variants of the virus had not arisen.
But the authors note that their findings remain relevant in dispelling suggestions that Covid-19 presents no risk to younger healthy adults, many of whom remain unvaccinated.
The researchers warn that policymakers must consider the risk of complications for those who survive Covid-19, not just mortality, when making decisions around easing restrictions.
They predict that Covid complications are likely to cause significant challenges for individuals and for the health and social care system in the coming years.
Disease severity at admission is a predictor of complications even in younger adults, so prevention of complications requires a primary prevention strategy, meaning vaccinationProfessor Calum Semple
Chief investigator and joint senior author of the study, Professor Calum Semple, from the University of Liverpool, said: “This work contradicts current narratives that Covid-19 is only dangerous in people with existing comorbidities and the elderly.
“Dispelling and contributing to the scientific debate around such narratives has become increasingly important.
“Disease severity at admission is a predictor of complications even in younger adults, so prevention of complications requires a primary prevention strategy, meaning vaccination.”
He told a press briefing: “I was actually really quite surprised. I was expecting the same relationship that we saw with death, in other words that the complications would be those in the frail and the elderly.
“And I was really quite distraught to see that we were talking about young people, previously fit and well, having complications.”
Prof Semple added: “My personal position and where this would influence my advice on the policy, is the message around Covid being a disease of the frail and the elderly and the young have got nothing to worry about.
“We now realise that paradigm is naive – sure young people will not die from this disease, but younger adults will be damaged by this disease and leave a legacy, which for the range of their lives could have a significant impact on what they want to do and how they want to live.”
The new study assessed in-hospital complications in adults aged 19 years or over with confirmed or highly suspected SARS-CoV-2 infection leading to Covid-19 disease.
Complications were assessed at multiple timepoints until discharge or, if the patient was not discharged, 28 days after admission.
While 80,388 patients were included in the study, 7,191 were excluded due to duplicated medical records, as they were not eligible for the study, or because no data was collected on the complications they experienced while in hospital.
Of the remaining 73,197 patients, 56% were men, 81% had an underlying health condition, 74% were white ethnicity, and the average age of the cohort was 71 years.
Almost one in three participants (32%, 23,092 of 73,197) in the study died.
Our study shows it is important to consider not just death from Covid-19 but other complications as well. This should provide policymakers with data to help them make decisions about tackling the pandemic and planning for the futureDr Thomas Drake
Overall, complications occurred in 50% of all participants, including in 44% (21,784 of 50,105) of participants who survived.
Dr Thomas Drake, co-author from the University of Edinburgh, said: “Our study shows it is important to consider not just death from Covid-19 but other complications as well.
“This should provide policymakers with data to help them make decisions about tackling the pandemic and planning for the future.
“We are still studying the participants in our study to understand the long-term effects of Covid-19 on their health.”
The study is published in The Lancet.