“There is a bidirectional relationship between Covid-19 and diabetes,” the experts wrote in an article published in the New England Journal of Medicine this month. The article was written by a group of 17 experts from around the world, including China, Britain and Australia.
“On the one hand, diabetes is associated with an increased risk of severe Covid-19. On the other hand, new-onset diabetes and severe metabolic complications of pre-existing diabetes … have been observed in patients with Covid-19,” the authors said. They called for more research to be done into Covid-related diabetes.
One of the authors, Professor Francesco Rubino from King’s College London, said the letter was written partly out of concern that new-onset diabetes had been observed in some people with no previous history of the disease.
“It is well known that severe illnesses or infections can increase blood sugar levels through stress-related mechanisms,” he said.
“We therefore think that some, or perhaps many, of the cases of new-onset diabetes observed in patients with Covid-19 could represent the unmasking of pre-existing but unknown diabetes or a temporary alteration that resolves with the resolution of the infection.”
Rubino said the evidence was still preliminary but worrisome as it suggested the hypothesis that the new coronavirus could possibly cause diabetes.
The coronavirus binds to ACE2 receptors which are expressed in organs such as the pancreas, thyroid gland and kidneys. These affect glucose metabolism, which leads the doctors to believe the pathogen “could complicate the pathophysiology of pre-existing diabetes or lead to new mechanisms of disease”.
“We have expected to see new cases of diabetes in relation to the infection and we are also expecting additional clinical problems at the level of other endocrine systems, potentially as long-term negative consequences of the viral encounter,” said Professor Bernhard Boehm of Nanyang Technological University in Singapore, who was one of the authors.
“In Singapore we have seen a couple of cases with ketoacidosis [a lack of endogenous insulin] plus the Covid-19 infection. In these cases the diabetes was not known before,” he said.
The authors said a new international registry – launched this week – would keep a record of patients with coronavirus-related diabetes, track their health and help investigate the link between the two diseases. The CoviDIAB Project aims to establish the extent of Covid-19-related diabetes and how best to manage it in patients.
Zhong-Lin Chai, head of the pathophysiology of diabetic complications laboratory at Monash University in Australia, said about 100 doctors from around the world had expressed interest in contributing data to the registry.
“We realised that there are some cases who became diabetic as a result of the new coronavirus infection. This phenomenon is also observed and reported in the 2003 Sars epidemic, which is also caused by [a] coronavirus,” he said.
“These viruses infect our cells with a protein called ACE2. We know pancreas islets have beta cells expressing high levels of ACE2. Therefore, the coronaviruses are able to infect and kill beta cells. Beta cells are the only cell population producing insulin. Coronavirus infection can cause insulin deficiency, causing diabetes.”
Boehm said health care teams and patients would both benefit from the registry which would allow patients to have their condition followed and to be treated with the best care.
Globally, about 20–50 per cent of patients infected with Covid-19 had diabetes, according to a paper published by The Lancet in April.
Data suggests that most people with Covid-19 have comorbidities, the existence of more than one disorder in the same patient. The most prevalent of these in Covid-19 patients are diabetes, cardiovascular disease and high blood pressure.
In regions heavily affected by the pandemic and based on reports from the US Centres for Disease Control and Prevention and other national health centres and hospitals, the risk of dying from Covid-19 was up to 50 per cent higher in patients with diabetes than in those who did not have diabetes, The Lancet paper said.
One reason for the greater incidence and severity of Covid-19 infection in people with diabetes was their increased risk of infection, it said.
There are 130 million people with diabetes in China, about one in every 10 mainland residents. Only 15.8 per cent of them had controlled their blood sugar level to a medical standard, official newspaper Science and Technology Daily said, citing a report from King’s College London.
“Until we know more about the issue, it is better to err on the safe side,” Rubino said. “For people who have diabetes it is prudent to get a fresh check of their blood sugar levels if they have not done this in a while and speak with their doctors to see if there is a need to optimise their medications to maintain their glycemic control as good as possible.”
“For those who do not have diabetes but have significant risk factors for it, such as persons who have pre-diabetes or have a family history of diabetes or have obesity, this is the time to increase efforts at maintaining a healthy lifestyle.”
Ni Xiaofen, a Shanghai woman in her 70s who was diagnosed with type 2 diabetes more than 10 years ago, said she was aware of the high risk for people with diabetes of becoming infected with Covid-19.
“It will lead to serious comorbidities of diabetes. So I have been extremely careful these past months. I must not get infected [with Covid-19],” she said.
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