Covid-19 infection linked with increased risk of new diabetes diagnosis, studies say

A study in the United States similarly found an increased incidence rate of diabetes in people who had recovered from Covid-19: a 40% increase in risk at least a year after infection. The researchers estimate that about 2 out of every 100 people who are infected with Covid-19 will have a new diagnosis of diabetes.

The more severe someone’s coronavirus infection was, the higher their risk of diabetes. For people who were treated in the ICU, the risk of diabetes jumped 276%. This connection could be related to the steroids that some patients get while receiving acute care in a hospital setting, which can increase blood sugar levels.

“This is not diabetes for a month or two after recovery. This is for a year out, and it’s happening certainly in people who are not hospitalized,” said lead researcher Dr. Ziyad Al-Aly, chief of research and development at the VA St. Louis Health Care System and a clinical epidemiologist at Washington University in St. Louis.

That study used the national databases for the US Department of Veterans Affairs to follow over 180,000 people after they got Covid-19. The research team compared this group’s outcomes to outcomes for a control group of over 4 million people from before the pandemic, along with another group of over 4 million people during the pandemic who did not get Covid-19.

Investigating the link

For many years, theories have circulated about inflammation from viral infections being implicated with diabetes. However, according to Dr. Robert Gabbay, chief scientific and medical officer at the American Diabetes Association, this is the first time studies have shown such a stark relationship between diabetes and a specific virus.

“There’s been a number of studies that do show that SARS-CoV-2 can attack the beta cells of the pancreas and may cause at least temporary harm, if not more permanent harm,” said Dr. Sara Cromer, an assistant in medicine at Mass General Hospital in the Division of Endocrinology, Diabetes, and Metabolism. She was not involved in the two new studies.

Beta cells are pancreatic cells that produce insulin. As these cells are destroyed by Covid-19 infection, the body may lose its ability to make insulin. This is similar to what happens in type 1 diabetes, an autoimmune disorder in which the body destroys its own beta cells and therefore cannot make insulin.

“It’s also possible that there’s the acute inflammation of getting Covid which may be present in low levels, even in asymptomatic or minimally symptomatic cases,” Cromer said. “That can lead to a short-term insulin resistance, which can maybe snowball or set off a chain of events that leads to more longer-term insulin resistance.”

This second theory would better explain the development of type 2 diabetes, the most common form, in which the body is still making insulin but grows resistant to it and thus cannot respond to it. Type 2 diabetics made up more than 99% of the newly diagnosed diabetes cases after Covid-19 infection that Al-Aly’s study identified.

Cromer said other factors could contribute to this increased risk for diabetes.

“When you’re diagnosed with SARS-CoV-2, you might stay at home a little while, you might eat differently, you might not exercise. There’s a number of ways that it might affect your lifestyle and behavior, and we don’t really know how those might interact with metabolic disease, either,” she said.