A cohort of scientists from around the world believes there is growing evidence that Covid-19 can cause diabetes in some patients.
Prof. Francesco Rubino from King’s College London leads the call for a comprehensive investigation into a possible link between the two diseases. After an increase in type 1 and type 2 diabetes in people with coronavirus, some doctors are even considering the possibility that the virus could trigger an entirely new form of diabetes by disrupting the metabolism of sugar.
Rubino first recognized the possibility of connecting during a tea party with coworkers via Zoom, where anecdote cases were exchanged.
Rubino and others have set up a registry to pool and analyze these reports. The registry’s lead investigators, who have received reports from more than 350 individual clinicians suspected of having encountered one or more cases of Covid-induced diabetes, said the numbers were difficult to ignore.
“In the last few months we have seen more cases of patients who had diabetes either during their Covid-19 experience or shortly afterwards. We are now beginning to believe that the link is likely true – the virus’s ability to cause glucose metabolism to malfunction, ”said Rubino.
If there was a biological link, it would be difficult to prove without an extensive database, he noted. “We said it is worth investigating as it could be a significant problem, especially given the size of the pandemic.”
Patients with pre-existing diabetes are at higher risk of serious complications with Covid-19 and are on the UK’s list of priorities to receive the vaccine. Links between other viruses and diabetes, as well as the way the Sars-CoV-2 virus, which causes Covid-19, penetrates multiple organs, has raised concerns.
“There is no doubt in my own mind. Covid-19 is certainly a cause of new diabetes, ”said Paul Zimmet, professor of diabetes at Monash University, Australia. “But we don’t quite understand – first, size, and second, which of the things we’ve assumed are the main factors.”
Scientists have suggested that because Sars-CoV-2 interacts with a receptor called ACE-2 to infiltrate cells in a number of organs, including the pancreas, it could disrupt sugar metabolism. Another possible explanation is the body’s excessive antibody response designed to fight the virus, overreact and attack the organs that are important in maintaining normal glucose levels.
“Well, these are all theories … theories that are not philosophical, but based on biology and experience with other viruses,” said Rubino, chairman of metabolic and bariatric surgery.
Other viruses – especially enterovirus infections – have been linked to the development of type 1 diabetes, in which the body attacks cells in the pancreas and prevents insulin from making. Enterovirus antibodies have been recorded at higher levels in pregnant mothers of children who later developed type 1 diabetes, and children who develop the disease tend to have more enterovirus infections compared to siblings who do not .
Dr. Sathish Thirunavukkarasu, an investigator at Canada’s McMaster University, conducted a review that included eight studies from different countries from the first five months of the pandemic. Together, Thirunavukkarasu and colleagues found 492 cases of newly diagnosed diabetes in 3,711 hospitalized Covid-19 patients, or a pooled proportion of 14.4%.
Those numbers include both Covid-19 patients first diagnosed with diabetes and people who previously had diabetes – but didn’t know they had the disease, he explained.
It’s hard to ignore the dramatic symptoms of type 1 diabetes where the body doesn’t make insulin. In type 2 diabetes, where the body cannot make enough insulin or the insulin is not working properly, symptoms are easy to miss because they appear gradually.
About 3.9 million people in the UK were diagnosed with diabetes as of 2019, but doctors believe there are thousands who go undiagnosed, a statistic that has likely worsened due to the pandemic.
Ian Braithwaite, an NHS doctor and co-founder of Habitual, a diabetes prevention and reversal company, pointed out that Thirunavukkarasu and colleagues’ analysis was limited to patients in the hospital as well, so it wasn’t clear if the cases of diabetes continued insist you have recovered or whether the rise in sugar levels increases the risk of diabetes in patients.
An increase in sugar levels might have nothing to do with diabetes and anything to do with the body’s response to infection. In addition, steroids used to treat certain patients with Covid-19 are known to increase blood sugar levels, doctors have pointed out.
Other recent studies have linked Covid-19 to varying degrees with emerging diabetes. Researchers in China who followed 2,469 Covid-19 patients after a six-month discharge from hospital recorded 58 (about 2.35%) cases of emerging diabetes. A separate, yet-to-peer study examining the results of 47,780 Covid-19 patients within five months of being discharged from hospital in England found that 4.9% of patients were diagnosed with diabetes after discharge .
