People who’ve had Covid-19 have a higher risk of developing diabetes, and that link seems to have persisted into the Omicron era, a new study finds.
Mounting evidence suggests Covid-19 infections are tied to a new diagnosis of diabetes, though it’s not clear whether this relationship is a coincidence or cause-and-effect.
For their study, published Tuesday in JAMA Network Open, researchers at Cedars Sinai Medical Center in Los Angeles studied the medical records of more than 23,000 adults who’d had Covid-19 at least once.
They looked to see how likely it would be for these people to get a new diagnosis of diabetes, high blood pressure or high cholesterol in the three months after their Covid-19 infection compared with the three months before it.
Because health care visits were often disrupted during the pandemic, many people are just getting around to getting routine physicals and checkups that they might have missed.
The researchers realized this could make them more likely to get a new diagnosis of a condition, such as diabetes, that they may have been developing anyway. To control for this, they also looked at the risk of something they called a benchmark diagnosis – a new diagnosis of either acid reflux or a UTI – as a way to address this bias.
The raw data showed that people who’d had Covid-19 had higher risks of being diagnosed with diabetes, high cholesterol and high blood pressure after their infections.
But when the researchers adjusted those numbers to account for the benchmark diagnosis, only the risk of diabetes remained significantly elevated. Covid-19 increased the odds of a new diabetes diagnosis by an average of about 58%.
Dr. Luke Wander, an assistant professor of medicine at the University of Washington in Seattle, said the findings echo those of several other studies.
The new study is notable because it adds recent data, said Wander, who was not involved in the research. It also used strategies to try to address shifts in health care during the pandemic.
Another strength of the study was that it included people who were diagnosed between March 2020 and June 2022, so it was able to estimate the risk even after the Omicron variant swept through the US.
Several studies have suggested that Omicron causes less severe Covid-19 infections than the variants that preceded it.
“One might expect that with a less severe viral infection, maybe you’d have less sort of off-target effects on your cardio-metabolic system,” said lead study author Dr. Alan Kwan, a cardiologist at Cedars Sinai.
“We did not really see that,” he said. “We saw, essentially, the pattern held throughout.”
The study is also notable because it looked at the role of vaccination, and it found that it may help protect against diabetes.
When the researchers parsed their data to distinguish between those who had been vaccinated against the coronavirus and those who weren’t, they found that the vaccinated had almost no increased risk of diabetes after Covid-19, but those were unvaccinated had nearly 80% higher odds of a new diabetes diagnosis. This difference was not statistically significant, however. Kwan says that if the researchers had had a little more data, the connection might be clearer.
Scientists aren’t quite sure how Covid-19 may increase the risk of diabetes. There could be several reasons, Wander said.
“It is plausible that the virus may directly act to change the body’s ability to make or use insulin,” she wrote in an email.
Or, she said, it’s possible that lifestyle changes made during the pandemic – perhaps less exercise and more junk food – may be contributing.
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“Lastly, we can’t exclude the possibility that this pattern is an artifact of increased laboratory testing among individuals with recent SARS-CoV-2 infection,” Wander said.
To really understand whether diabetes is a different disease in the wake of the pandemic, Wander said, you’d need studies that follow people to collect information about pandemic-related societal factors and changes in the body’s ability to make and use insulin.