People with diabetes or heart disease are known to be more at risk from coronavirus, which is starting to spread rapidly in the UK and internationally. That is a concern for the 7.4 million Britons who have some form of cardiac or circulatory disease, which includes 4.8 million people with diabetes.
The common risk factor is the lungs, because with both types of patients it is that organ which is likely to be damaged by the coronavirus. Their poor underlying health means they are in greater danger of suffering serious medical harm from Covid-19 than people with good health.
Jon Cohen, emeritus professor of infectious diseases at Brighton and Sussex medical school, said: “The coronavirus causes an infection of the lungs – a pneumonia. When the lungs get an infection – any kind of pneumonia, not just coronavirus – the airspaces fill up with fluid caused by the inflammation. So the body has to work harder to get oxygen into the blood.
Heart and lungs
“The heart and the lungs work as a closely integrated ‘team’, so when there is a pneumonia the heart has to work harder, and so obviously if there is pre-existing heart disease that puts extra strain on the heart.”
Early reports from the outbreak that began in China suggested 40% of people who were ill enough to be treated in hospital because of coronavirus had either cardiovascular disease or cerebrovascular disease – affecting the flow of blood in their brain – such as a stroke.
“That statistic doesn’t mean people with heart disease are more likely to contract the coronavirus,” said Orly Vardeny, an associate professor of medicine at the Minneapolis VA Health Care System and University of Minnesota. “It just means that those folks are more likely to have complications once they do get it.”
People who have fatty buildups or plaques in their arteries could be at risk of having a heart attack because viral illnesses similar to Covid-19 can destabilise these plaques, which can then block an artery leading to the heart, according to Vardeny.
Diabetics, with either type 1 or type 2, are at risk from Covid-19 for similar reasons.
“Patients with diabetes often have complications involving the heart, but also the kidneys, and in the same way any extra strain on the body from the infection can cause secondary problems in those organs. Furthermore, we know that diabetics’ immune systems are not quite as good as fighting infections as non-diabetics,” added Cohen.
“Coronavirus can cause more severe symptoms and complications in people with diabetes. If you have diabetes and you have symptoms such as cough, high temperature and feeling short of breath you need to monitor your blood sugar closely and call NHS 111,” said Dan Howarth, the head of care at Diabetes UK.
The risk to patients in both groups depends on each person’s health, such as how long they have had their illness, how often they suffer complications and any other conditions they have as well, such as a breathing problem.
But case fatality rates – the proportion of people with an illness who die – show that the over-65s are five times more likely to die than those in the lowest risk groups. And in general terms older people are the likeliest to have underlying health disorders like these.