People who were hospitalised for COVID-19 and survived for at least a week after discharge, were more than twice as likely to die or be readmitted to the hospital in the next several months, compared with the general population, a large study conducted in England found.
The findings were presented in PLOS Medicine by Krishnan Bhaskaran and colleagues from the London School of Hygiene and Tropical Medicine, University of Oxford and clinical software provider TPP.
Previous research has suggested that people with COVID-19 might face a greater risk of health issues for several months after their initial infection. However, evidence on this topic remains limited.
To help clarify long-term health risks for people with COVID-19, Bhaskaran and colleagues focused on those who had been hospitalised for the disease. The researchers conducted a statistical analysis of electronic health records from the database OpenSAFELY, evaluating data on nearly 25,000 patients who had been discharged after being in hospital for COVID-19 in 2020, and for comparison, more than 100,000 members of the general population.
The analysis showed that, compared with the general population, people who had been admitted for COVID-19 and lived for at least one week after discharge had twice the overall risk of hospital readmission or death in subsequent months. They also faced nearly five times the risk of death from any cause.
To account for risks after hospitalisation for an infectious disease, the researchers also considered data from more than 15,000 people who had been admitted for influenza in 2017-19. Statistical analysis found that, compared with the flu patients, COVID-19 patients faced a slightly lower combined risk of hospitalisation or death overall. However, people who had been admitted for COVID-19 had a greater risk than flu patients of death from any cause, a greater risk of hospital readmission or death resulting from their initial infection, and a greater risk of death due to dementia.
Overall, these findings align with other research showing increased risks of subsequent health issues for people who have had COVID-19. The authors suggest these risks could be mitigated by policies to increase monitoring of COVID-19 patients after discharge and to raise awareness of potential complications.
Bhaskaran adds, “Our findings suggest that people who have had a severe case of COVID-19 requiring a hospital stay are at substantially elevated risk of experiencing further health problems in the months afterwards. Patients and their doctors should be aware of this so that any problems that develop can be treated as early as possible. Our findings also highlight the importance of getting vaccinated, which is the best tool we have for preventing severe COVID-19 in the first place.”
Study details
Overall and cause-specific hospitalisation and death after COVID-19 hospitalisation in England: A cohort study using linked primary care, secondary care, and death registration data in the OpenSAFELY platform
Krishnan Bhaskaran, Christopher T. Rentsch, George Hickman, William J. Hulme, Anna Schultze, Helen J. Curtis, Kevin Wing, Charlotte Warren-Gash, Laurie Tomlinson, Chris J. Bates, Rohini Mathur, Brian MacKenna, Viyaasan Mahalingasivam, Angel Wong, Alex J. Walker, Caroline E. Morton, Daniel Grint, Amir Mehrkar, Rosalind M. Eggo, Peter Inglesby, Ian J. Douglas, Helen I. McDonald, Jonathan Cockburn, Elizabeth J. Williamson, David Evans, John Parry, Frank Hester, Sam Harper, Stephen JW Evans, Sebastian Bacon, Liam Smeeth, Ben Goldacre.
Published in PLOS Medicine on 25 January 2022
Abstract
Background
There is concern about medium to long-term adverse outcomes following acute Coronavirus Disease 2019 (COVID-19), but little relevant evidence exists. We aimed to investigate whether risks of hospital admission and death, overall and by specific cause, are raised following discharge from a COVID-19 hospitalisation.
Methods and findings
With the approval of NHS-England, we conducted a cohort study, using linked primary care and hospital data in OpenSAFELY to compare risks of hospital admission and death, overall and by specific cause, between people discharged from COVID-19 hospitalisation (February to December 2020) and surviving at least 1 week, and (i) demographically matched controls from the 2019 general population; and (ii) people discharged from influenza hospitalisation in 2017 to 2019. We used Cox regression adjusted for age, sex, ethnicity, obesity, smoking status, deprivation, and comorbidities considered potential risk factors for severe COVID-19 outcomes.
We included 24,673 postdischarge COVID-19 patients, 123,362 general population controls, and 16,058 influenza controls, followed for ≤315 days. COVID-19 patients had median age of 66 years, 13,733 (56%) were male, and 19,061 (77%) were of white ethnicity. Overall risk of hospitalisation or death (30,968 events) was higher in the COVID-19 group than general population controls (fully adjusted hazard ratio [aHR] 2.22, 2.14 to 2.30, p < 0.001) but slightly lower than the influenza group (aHR 0.95, 0.91 to 0.98, p = 0.004). All-cause mortality (7,439 events) was highest in the COVID-19 group (aHR 4.82, 4.48 to 5.19 versus general population controls [p < 0.001] and 1.74, 1.61 to 1.88 versus influenza controls [p < 0.001]). Risks for cause-specific outcomes were higher in COVID-19 survivors than in general population controls and largely similar or lower in COVID-19 compared with influenza patients. However, COVID-19 patients were more likely than influenza patients to be readmitted or die due to their initial infection or other lower respiratory tract infection (aHR 1.37, 1.22 to 1.54, p < 0.001) and to experience mental health or cognitive-related admission or death (aHR 1.37, 1.02 to 1.84, p = 0.039); in particular, COVID-19 survivors with preexisting dementia had higher risk of dementia hospitalisation or death (age- and sex-adjusted HR 2.47, 1.37 to 4.44, p = 0.002). Limitations of our study were that reasons for hospitalisation or death may have been misclassified in some cases due to inconsistent use of codes, and we did not have data to distinguish COVID-19 variants.
Conclusions
In this study, we observed that people discharged from a COVID-19 hospital admission had markedly higher risks for rehospitalisation and death than the general population, suggesting a substantial extra burden on healthcare. Most risks were similar to those observed after influenza hospitalisations, but COVID-19 patients had higher risks of all-cause mortality, readmission or death due to the initial infection, and dementia death, highlighting the importance of postdischarge monitoring.
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