Among all the manifestations and complications of COVID-19, yet another puzzling question is emerging — is the virus triggering cases of diabetes?
Like many doctors around the world, Dr. Mihail Zilbermint began noticing something strange midway in the pandemic.
More and more people seemed to be suddenly developing diabetes.
“My team usually manage about 16 to 17, or 18 patients with diabetes per day,” Zilbermint told CTV News. “And our numbers increased up to 30 per day.”
Zilbermint is an endocrinologist and an associate professor with Johns Hopkins School of Medicine in Maryland. The sudden change was surprising, he said, and worrying.
A diagnosis of diabetes was also a shock to John Kunkel, who lives in Arkansas, and had just recovered from a serious case of COVID-19 when he discovered his pancreas had stopped making enough insulin, forcing him into daily blood sugar testing, and metformin to manage his diabetes.
Kunkel tested positive for COVID-19 at the end of June 2020.
He texted his doctor immediately after realizing that he had lost his sense of taste. By the time he arrived at the doctor’s office, he already had a fever of 101 degrees.
“By 7:30 that night I was in the emergency room with 103.5 fever,” he said. “So I went from really losing my taste at 11 o'clock, being in the hospital at night with a very high fever.”
His fever was worryingly high for almost two weeks straight. He was in the emergency room five times.
In July, things took a turn for the worse during his recovery.
“I'll never forget the day,” he said. “It was July 30 when I had bloodwork done.”
When his results came back, it was clear there was a problem with his blood sugar.
“So it's like, “hey, you've got diabetes, we've got to start treating it immediately,” because it was so high,” Kunkel said.
“A lot of it was, you know — why? I didn't have it before. And it was the big question that all the doctors would give is, they really don't know.”
Doctors around the world are now sharing similar case reports of sudden onset diabetes after COVID-19 infection, finding that the link is strongest among patients who were hospitalized with the virus.
“We clearly see people without previous diabetes developing diabetes,” Dr. Remi Rabasa-Lhoret, with the Montreal Clinical Research Institute, told CTV News. “It is highly probable that COVID-19 is triggering the disease.”
Studies suggest that up to 14 per cent of COVID-19 patients may develop sudden onset diabetes.
“We've seen this with influenza and other infections […] but the magnitude of what we see with COVID-19 is above what we're used to,” Rabasa-Lhoret said.
People with diabetes are already more at risk of experiencing severe outcomes if they contract COVID-19, and now the virus may be putting people more at risk of developing diabetes — a connection that an article in the New England Journal of Medicine described as “a bidirectional relationship.”
So why is this happening? Doctors and researchers are investigating, but a specific reason hasn’t been pinpointed yet.
Among the theories is that this could be a side effect of a steroid used to treat COVID-19.
Zilbermint said that patients who experience complications due to COVID-19 frequently receive a steroid medication called Dexamethasone.
“[It’s] our standard therapy for those who have low oxygen levels, and the side effect of this medication is high sugar levels, or diabetes,” he said. “So it's possible that the medications they use to treat COVID may also contribute to increased risk of developing diabetes.”
Kunkel said he was on a round of steroids for an entire month, and now he’s unsure if this contributed to his diagnosis.
“I had three rounds, so that could have elevated and caused it,” he said.” So there's all of these really unknowns.”
There are also signs that the novel coronavirus itself could affect the body in ways that would cause them to develop diabetes.
“There are some suggestions that COVID-19 could go directly in the cells which produce insulin, in the pancreas, and damage them,” Rabasa-Lhoret said.
Zilbermint added that the virus may be able to change the way that cells metabolize glucose itself.
Acute onset of diabetes was also reported more among patients with SARS a decade ago, he said, “compared to those without the SARS pneumonia, […] which I think is important to mention.”
Another thought is that perhaps it’s that the infection tips people who are at risk of developing diabetes into a diagnosis sooner.
“It's possible that [a] patient lives with pre-diabetes for many years and didn't know that,” Zilbermint said. “Now they have COVID-19 infection, and the infection is pushing them towards developing diabetes.”
That’s something Kunkel has considered.
“It could be that, OK, I was on the verge of getting diabetes, and COVID-19 actually pushed it over the edge,” he said.
Some doctors wonder if it’s a new form of diabetes altogether.
In Type 1 diabetes, patients’ immune system destroys beta cells that produce insulin.
However, COVID-19 patients who develop diabetes can also exhibit insulin resistance which is found in Type 2 diabetes. (Insulin resistance is when cells are “resistant” to the hormone insulin, and as a result can’t use glucose. The pancreas produces more insulin and blood sugar spikes.)
Some doctors believe the sudden-onset diabetes after a COVID-19 infection may be a novel condition which features both Type 1 and Type 2 diabetes.
“The main question is, is this going to be transient, or is this going to be permanent?” Rabasa-Lhoret said. “And on the short term, we don't know.”
It’s the questions that haunt patients like Kunkel, as well as the doctors who treat these patients.
But work is being done to figure out what is going on, and how best to treat patients.
“A number of endocrinology specialists and diabetes experts around the world are looking into this,” Zilbermint said.
“For example, my colleagues at the King's College in London and U.K. already established a robust database where all the researchers, clinicians, doctors can submit the information about their patients into a global registry.
This new global database will try to collect all the cases in a bid to understand whether the coronavirus infection truly has yet another nasty side effect.
“I'm sure we'll see more research studies coming out of this registry in the coming months,” Zilbermint said.