Two-thirds of coronavirus-related hospital admissions are due to the patient enduring at least one of four underlying health conditions, research suggests.
The infection is thought to be mild in four out of five cases, however, it can trigger a disease called COVID-19.
Statistics have repeatedly flagged certain medical disorders raise the risk of coronavirus complications, prompting some individuals to shield entirely at home and be prioritised for a vaccine.
To learn more, scientists from Tufts University in Massachusetts used a mathematical simulation to estimate the number of coronavirus hospital admissions that may have been prevented if US residents did not have four common disorders.
Among the more than 906,000 coronavirus hospitalisations that occurred in adults as of 18 November 2020, nearly a third (30%) were linked to obesity.
Just over a quarter (26%) were attributed to high blood pressure, 21% to diabetes and 12% to heart failure; when the organ's muscle does not pump blood as efficiently as it should.
When the four conditions were combined, the results suggest just under two-thirds (64%) of coronavirus hospitalisations could have been prevented.
This combination of disorders occurs with so-called metabolic syndrome; defined as a cluster of conditions – like high blood pressure, elevated cholesterol levels and excess fat around the waist – that together raise the risk of heart disease, strokes and type 2 diabetes.
"While newly authorised COVID-19 vaccines will eventually reduce infections, we have a long way to go to get to that point," said lead author Dr Dariush Mozaffarian.
Jabs by Pfizer-BioNTech and Moderna have been signed off in the US. The UK has a third vaccine in its immunisation arsenal, developed by AstraZeneca-University of Oxford.
"Our findings call for interventions to determine whether improving cardiometabolic health will reduce hospitalisations, morbidity and healthcare strains from COVID-19," said Dr Mozaffarian.
"We know changes in diet quality alone, even without weight loss, rapidly improve metabolic health within just six to eight weeks.
"It's crucial to test such lifestyle approaches for reducing severe COVID-19 infections, both for this pandemic and future pandemics likely to come."
The scientists based their estimations on the four conditions' prevalence among more than 5,000 hospitalised coronavirus patients in New York earlier in the pandemic.
This was extrapolated out using national data, taking into account the age, sex, ethnicity and underlying health of adults with the infection.
Finally, the scientists estimated the number of coronavirus cases severe enough to require hospital care due to the presence of one or more of the underlying conditions.
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The results, published in the Journal of the American Heart Association, further suggest reducing the prevalence of each disorder by 10% would prevent around 11% of all coronavirus admissions.
"Medical providers should educate patients who may be at risk for severe COVID-19 and consider promoting preventive lifestyle measures, such as improved dietary quality and physical activity, to improve overall cardiometabolic health," said study author Meghan O'Hearn.
"It's also important for providers to be aware of the health disparities people with these conditions often face."
Statistics have repeatedly shown the risk of coronavirus complications rises with age.
Diabetes, for example, was found to be behind around 8% of the coronavirus hospitalisations among adults under 50, compared to just under a third (29%) of those in patients aged 65 or over.
Obesity, however, had an "equally detrimental impact on COVID-19 hospitalisations across age groups".
People of a non-white ethnicity have also repeatedly been shown to endure worse coronavirus complications and related death rates amid the pandemic.
The Tufts' results suggest Black adults with the four conditions are more likely to be hospitalised than their white counterparts, across all ages. Hispanic individuals with diabetes and obesity are also more likely to require care.
Diabetes was found to cause around a quarter (25%) of hospitalisations among white patients aged 65 or over, compared to 32% and 34% among Black and Hispanic adults, respectively.
The combined four conditions caused 50% of hospitalisations in Black people aged 18 to 49, versus 39% for their white counterparts.
"National data show Black and Hispanic Americans are suffering the worst outcomes from COVID-19," said Dr Mozaffarian.
"Our findings lend support to the need for prioritising vaccine distribution, good nutrition and other preventive measures to people with cardiometabolic conditions, particularly among groups most affected by health disparities.
"Policies aimed at reducing the prevalence of these four cardiometabolic conditions among Black and Hispanic Americans must be part of any state or national policy discussion aimed at reducing health disparities from COVID-19."
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