Determining 'COVID age' online to assess vulnerability

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It's known that there are a variety and interplay of risk factors that determine vulnerability to and morality risk of  the coronavirus, writes MedicalBrief. Scientists have developed an online calculator to determine risk that goes beyond a rough and ready sorting according to raw age, to determine "COVID age".

As anybody who has followed the news for the last eight months will know, COVID-19 is a far deadlier threat to the old than the young. The Daily Telegraph reports the over-80s make up more than half (53%) of patients who have died in English hospitals after testing positive for the virus, and 92% were over 60, according to data from Public Health England (PHE).

But some doctors are now worried that the publicʼs overwhelming focus on age – whilst undeniably a huge factor – is making broadly healthy older people more frightened than they need to be, and lulling younger patients with conditions like obesity and diabetes into thinking they have nothing to fear.

“Part of me feels there is a need to get away from raw age in the risk (sorting) tools,” says Dr Matthew Knight, consultant respiratory physician at West Hertfordshire NHS Trust. “My dad is 75 and goes for an eight to 10-mile walk with the dogs every morning – heʼs probably fitter than I am. His biological age isn't going to be 75.”

Instead, some in the medical world think it might be more helpful to think of your ‘COVID ageʼ – how various factors like age, weight, kidney function and diabetes coalesce to determine your vulnerability to the virus. One group of data scientists in the US has created an online calculator in which users input various pieces of health data to find out their precise COVID risk score. Knight thinks COVID age could be a “useful concept”, although he notes that doctors are not yet using it to assess patients.

He says respiratory doctors have long used the concept of lung age to assess a patientʼs respiratory strength, in which patients are asked to blow as hard as they can on a spirometer. “If youʼre 28, but you blow an average that is more appropriate for a 34-year-old, then your lung age is 34,” he explains. So, what are the factors that contribute to your COVID age? Here, we look at six. There is no getting around the fact that your age has a “humongous” impact on your risk of dying or becoming seriously ill if you contract COVID, says Knight.

The risk of death for a healthy young person is “very low indeed”, according to Professor Sir David Spiegelhalter, chair of the Winton Centre for Risk and Evidence Communication at the University of Cambridge, said in the summer that under-35s were more likely to die in a road accident this year than from COVID. But that risk rises on a steep age gradient, he said, doubling roughly every five to six years.

The US Centres for Disease Control and Prevention (CDC) reports that people aged 64 to 75 are five times more likely to end up in hospital than those aged 18 to 29, with a 90 per cent higher risk of death. The one thing that is not clear is whether there is something fundamental about being older – such as the immune system becoming less efficient with time – or if our age is just shorthand for being in worse health.

“Age is also tied to heart disease, lung disease, Type 2 diabetes, so itʼs hard to disentangle whether it is their age or comorbidities (other health problems),” Professor Ravindra Gupta, from the University of Cambridge, is quoted as saying.

A review of studies by PHE found that being overweight or obese (categories into which almost two-thirds of the UK public falls) brings a sharp rise in your risk of hospital admission or death. In a study of nearly 17,000 COVID patients in UK hospitals, for example, those who were obese – with a body mass index (BMI) of more than 30 – had a 33% increased chance of dying compared with those who were not obese.

Another study found that nearly three-quarters (73%) of COVID patients in intensive care were either overweight or obese, compared with 64% in the UK population. Weight is seen as such a major factor that some doctors have called for a rapid expansion in National Health Service (NHS)-funded weight loss surgery. They hope their message will fall on receptive ears in Downing Street, where Boris Johnson reportedly told colleagues that he is preparing a “more interventionist” drive against obesity, following his own brush with the virus in the spring.

The prime minister is said to have become convinced that his weight is the reason he ended up in intensive care while his slimmer colleagues suffered only mild symptoms. Diabetes is also a major risk factor, possibly because fluctuating or elevated levels of glucose leaves patients with weakened immunity.

One third of all hospital deaths from coronavirus in England have been among diabetics, according to research led by the national clinical director for diabetes and obesity, which examined 23,804 COVID-19 deaths in UK hospitals between March and May. Of those who died, 7,466 suffered from Type 2 diabetes, while 365 suffered from Type 1. Some doctors think the condition might double your mortality risk (you can see how different health conditions affect your COVID risk in the chart below). However, 85% of people with Type 2 diabetes are also overweight, making it difficult for statisticians to separate the two factors.

“If you have diabetes and you have symptoms such as a cough, high temperature and feeling short of breath you need to monitor your blood sugar closely and call the NHS 111 phone service,” Dan Howarth, head of care at Diabetes UK, is quoted as saying. Kidney disease might double a patientʼs risk of dying from COVID, according to a study of intensive care units (ICUs) in London and Birmingham published earlier this month by Imperial College London – findings that indicate “extreme risk” for more than three million people in the UK.

The figures suggest that patients with either pre-existing renal problems or those caused by the virus have a significantly worse chance of survival than people with better-known risk factors such as lung damage. Between March 10 and July 23, ICU patients with acute kidney injury – most likely caused by COVID – had a mortality rate of 48%, compared with 21% in ICU patients without any kidney problems. For those with pre-existing chronic kidney disease, there was a 50% chance of death. Researchers called on ICU doctors to be on high alert for kidney problems. “Kidney disease is another big risk factor,” says Knight. “Weʼre not just talking necessarily about patients who need dialysis, just kidneys that are not functioning well, too.”

Cancer patients undergoing treatment are more susceptible because of their compromised immune system. “Various cancer drugs and treatments, like chemotherapy, mean your immune system may be suppressed,” says Fan Chung, a professor of respiratory medicine at Imperial College London. “This would increase your chances of catching (COVID). And if you do get it while you have cancer, you would probably fare worse than somebody with the virus who didnʼt have cancer.”

Those suffering from mental illness are slightly more likely than average to suffer worse outcomes from COVID – and doctors arenʼt sure why. “Mental health problems appear to be a soft predictor of poorer outcomes,” says Knight. “The cause of that weʼre not entirely sure. That may well be due to a general marker of not looking after yourself very well, or it may be due to some other genetic factor that we donʼt yet know.”


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