A Canadian study looking at more than 600,000 people has found a higher rate of new diabetes diagnoses in those who’d been infected with COVID-19.
The study, which is published in JAMA Network Open, suggests that COVID may be responsible for a 3% to 5% excess burden of diabetes at the population level.
The Canadian researchers drew on data from the British Columbia COVID-19 Cohort: a study that collected the health records of people tested for SARS-CoV-2 in the province from January 2020 to December 2021.
From this cohort, 125,987 people tested positive to COVID-19. The researchers matched each of these people with four unexposed people of the same age, sex, and test date.
This gave them a sample of 629,935 people, a fifth of whom had been infected with SARS-CoV-2.
They then went looking for incident diabetes – that is, a new diagnosis – more than 30 days after the COVID test.
The COVID-positive group had a rate of 672.2 new diabetes diagnoses per 100,000 people, significantly higher than the control group’s rate of 508.7 new diagnoses per 100,000.
This translates to roughly 3-5% extra diabetes cases at a population level, according to the researchers’ analysis.
“Our overall results were consistent with several other studies finding higher risk of incident diabetes after SARS-CoV-2 infection; however, the increase in risk was lower in our analysis compared with other studies,” they write in their paper.
They suggest a few differences in study populations for this discrepancy.
It’s not yet clear why there’s a link between COVID infection and diabetes.
In their paper, the researchers point out that SARS-CoV-2 has been shown to attack pancreatic cells which are involved with insulin production. Low-grade inflammation from COVID could also play a role. But these processes are still poorly understood.
“Our study highlights the importance of health agencies and clinicians being aware of the potential long-term consequences of COVID-19 and monitoring people after COVID-19 infection for new-onset diabetes for timely diagnosis and treatment,” conclude the researchers.