It is well established that cardiovascular disease was associated with more severe outcomes during the first wave of COVID-19, including an increased risk of hospitalisation and death. New research suggests that this may have also applied to people with an elevated 10-year cardiovascular risk score, even in the absence of overt disease. This group has not previously been identified as a risk group for severe COVID-19.
The observational study, which has not yet been peer reviewed, was led by researchers from the London School of Hygiene and Tropical Medicine (LSHTM), University College London and the University of Bristol, and will be presented at this year's European Congress of Clinical Microbiology & Infectious Diseases (ECCMID), to be held in Lisbon, Portugal on April 23-26.
Study Details
The team used linked electronic health record data from almost a million adults aged 40-84 years registered at GP practices across England during the first wave of the pandemic in 2020. They calculated the incidence and risk of laboratory-confirmed SARS-CoV-2 and related deaths, intensive care unit admissions, and hospitalisations among adults at raised and low cardiovascular risk based on QRISK3 scores. These scores combine a range of factors, including body mass index, smoking history, blood pressure, cholesterol, age, social deprivation, and ethnicity. A score of 10% or greater, meaning a 10% or higher chance of a heart attack or stroke within the next 10 years, was classed as denoting raised risk, and a score of less than 10% deemed low risk.
Among the initial sample of 949,973 individuals, 113,142 (12%) had existing CVD, 303,558 (32%) were classed as being at raised risk of CVD, and 533,273 (56%) at low risk.
Between March 12 and September 29, 2020, SARS-CoV-2 was confirmed in 4017 participants (average age 58 years, 50% male), giving an adjusted incidence of 5.5 per 1000 (95% CI 5.3 to 5.7). Incidence was similar among the 1144 individuals with raised cardiovascular risk, at 4.9 per 1000 (95% CI 4.6 to 5.1), as among the 1819 people with low cardiovascular risk, at 4.5 per 1000 (95% CI 4.3 to 4.7).
Among those with COVID-19, outcomes included:
- Hospitalisation 414.4 /1000 (95% CI390.6 to 439.8) (n=1091)
- ICU admission 60.4/1000 (95% CI 51.7 to 70.6) (n=159)
- Mortality 218.8 /1000 (95% CI 201.6 to 237.4) (n=576)
Occurrence of Severe Outcomes 'Far Higher' in People with Elevated Risk
Rates of all of these adverse outcomes were substantially higher in those with raised cardiovascular risk compared with those at low risk:
- Hospitalisation 607.2 [552.5 to 667.4] versus 169.3 [149.1 to 192.3]/1000
- ICU admission 97.4 [77.0 to 123.4] vs 35.7 [27.1 to 47.1]/1000
- Mortality 310.7 [272.2 to 354.6] vs 23.6 [16.8 to 33.2]/1000
These rates were adjusted for additional sociodemographic and clinical confounders that are not included in the QRISK3 score calculation, including alcohol intake, primary care attendance frequency, prescription of antiplatelets, prescription of anticoagulants, chronic liver disease, chronic respiratory disease, asthma, dementia, chronic neurological disease, cancer, and immunosuppression.
After adjustment, hazard ratios (HR) in those with raised cardiovascular risk were:
- Hospitalisation HR 2.78 [2.24-3.45]
- ICU admission HR 2.99 [1.80-4.96]
- Mortality HR 6.84 [4.18-11.19]
People with elevated cardiovascular risk "showed a substantially greater risk of severe outcomes", the team concluded.
Author Jennifer Davidson, a PhD student in public health research at the LSHTM said: "Although the risk of contracting COVID-19 infection appears similar among individuals with raised and low cardiovascular risk, the occurrence of severe outcomes is far higher in those at elevated risk."
She added: "Our study is one of the largest population-based studies with a comprehensive measure of cardiovascular risk."
Expecting Similar Results with Larger Dataset
The authors noted that this is an observational study, so no firm conclusions can be drawn about cause and effect, and they cannot rule out the possibility that other unmeasured factors may have affected the results. However they suggested that investing in strategies to improve cardiovascular health could reduce the severity of COVID-19 across the population.
Senior author Dr Charlotte Warren-Gash, associate professor of epidemiology and honorary consultant in public health at the LSHTM, said: "Because many of the cardiovascular risk factors associated with more severe consequences from COVID-19 are potentially modifiable, clinicians and policy makers should consider that strategies which improve cardiovascular health may also improve outcomes for people following COVID-19."
The researchers are currently updating their findings with a dataset of over 6 million individuals to confirm the initial results. This will be presented at the meeting and then submitted for a peer-review publication.
Ms Davidson told Medscape UK that their analysis of the larger dataset is still in progress and they do not yet have results to share. However: "At this point we do not anticipate the results of the larger dataset will be materially different to our initial analysis."
The study was funded by the BMA Medical Research Foundation/ Rosetrees Trust COVID-19 grant and by the Wellcome Trust.
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