Doctors add diabetes to the list of COVID-triggered conditions

Since the start of the coronavirus outbreak, doctors have found that people living with diabetes are at an increased risk of having severe COVID-19 symptoms. But the relationship between these two diseases appears to be two-way: Infection with the novel coronavirus may trigger stress-related diabetes, an often temporary form of the disease that occurs when the body begins producing hormones to fight the foreign invader that interfere with normal insulin function. Now, a group of leading diabetes researchers have published a letter in the New England Journal of Medicine announcing a new initiative to track this evolving relationship between diabetes and COVID-19.

The CoviDIAB Project is a global registry of COVID-19 patients who develop diabetes after infection with the novel coronavirus. The project launched Friday, but already has 50 requests from researchers around the globe to upload pertinent data, says Francesco Rubino, one of the letter’s authors and a professor of metabolic and bariatric surgery at King’s College London.

“Given the very short history of human contact with COVID-19, this registry will rapidly help us understand how COVID-19-related diabetes develops, its natural history, and its best management,” the registry website reads.

Anecdotal evidence of the link between infection with COVID-19 and subsequent development of diabetes emerged very rapidly when cases in New York City spiked, says Jeffrey Mechanick, a professor of medicine at Mount Sinai who was on the front lines with his colleagues during the worst of the first wave of the new disease in New York City.

Patients who had no history of diabetes or pre-diabetes were showing up with severe hyperglycemia, he says. High blood sugar, or hyperglycemia, occurs when the body does not produce enough insulin (Type 1 diabetes) or cannot effectively use the insulin it produces (Type 2 diabetes). It can have wide-reaching effects on the body.

Although the patients technically were presenting with diabetes, that term “sort of falls short of how extreme the hyperglycemia was,” says Mechanick. Planning for treating hyperglycemia using usual measures like insulin drips and monitoring, among other things, became a normal part of pandemic planning for Mount Sinai and other hospitals, he says.

It’s not yet clear exactly what the mechanical relationship between extreme hyperglycemia and COVID-19 is, but Rubino and his colleagues believe it’s related to how the virus binds to the body’s cells. “The virus binds to a protein that is called [the] ACE2 receptor, and this protein is basically like a keyhole for the virus to enter the cell,” says Rubino.

The lungs have a lot of ACE2 receptors, which helps explain the virus’s respiratory impacts. But many other tissues have this same protein, says Rubino, especially the pancreas, fat tissue, small intestine, liver, and kidneys. “All [these organs] play a critical role in sugar metabolism,” he says.

It’s not known, at present, whether the diabetes caused by COVID-19 will abate for all patients as they recover, says David Nathan, a professor of medicine at Harvard University.

Nathan notes that incidences of stress-related diabetes often disappear once the triggering illness resolves—another example is gestational diabetes, which resolves following pregnancy for most people. Anecdotally, he says he’s seen patients with COVID-19 have their diabetes resolve in a similar fashion, but there’s no evidence whether that’s true for everyone.

Additionally, it’s not yet clear how much more hyperglycemic COVID-19 patients are likely to get compared to patients who develop stress hyperglycemia from other diseases. Anecdotal evidence seems to indicate it’s a big difference, but research is needed.

Getting more case studies will help researchers better understand what’s going on. In the meantime, Rubino suggests watching for diabetes symptoms if you think you might have COVID-19. These include intense thirst, frequent bathroom breaks, confusion, blurred vision, and extreme fatigue. If someone has any of these symptoms, “they should seek medical attention sooner rather than later,” he suggests.