This transcript has been edited for clarity.
Does having had a COVID-19 infection increase your risk for the development of diabetes subsequently? Some data say yes and other data say no. No matter what, it’s obviously important to screen people for diabetes routinely, pandemic or not. Remember, screening should start at age 35.
For over a decade, we have known that SARS-type viruses bind to beta cells. This could cause either direct damage to the beta cell or in some way trigger beta cell autoimmunity. We also know that COVID-19 infection increases the levels of inflammatory mediators, which could cause damage to beta cells and potentially to insulin receptors. There is a potential that having had a COVID-19 infection could increase rates of developing type 1 and/or type 2 diabetes.
Dr. Anne L. Peters
However, there are other possible causes for people to develop diabetes after having a COVID-19 infection. A COVID-19 infection could cause one to seek medical care, unmasking latent type 1 and/or type 2 diabetes by causing infection-related insulin resistance and worsening preexisting mild hypoglycemia. In addition, people could have sought more medical care in the years since the pandemic has been ebbing, which may make it look like cases have increased.
For example, during the worst of the pandemic, I had multiple referrals for “COVID-19–caused new-onset diabetes” only to find that the patient had an A1c level above 10% and a history of mildly elevated blood glucose levels. This suggests to me that COVID-19 did not cause the diabetes per se but rather worsened an underlying glucose abnormality.
Since the pandemic has improved, I have also seen people diagnosed with type 2 diabetes that I think is associated with pandemic-related weight gain and inactivity.
The bigger issue is what is happening to people after COVID-19 infection who lack risk factors. What about those who we didn’t think were at high risk to get diabetes to begin with and didn’t have prediabetes?
An article by Xie and Al-Aly in The Lancet Diabetes & Endocrinology showed an increase in rates of diabetes in a large VA cohort among those who had a COVID-19 infection compared with both a contemporaneous control who did not have COVID-19 and a historical control. The researchers looked at the patient data 1 year after they’d had COVID-19, so it wasn’t the immediate post–COVID-19 phase but several months later.
They found that the risk for incident type 2 diabetes development was increased by 40% after adjusting for many risk factors. This included individuals who didn’t have traditional risk factors before they developed type 2 diabetes.
What does this mean clinically? First, pandemic or not, people need screening for diabetes and encouragement to have a healthy lifestyle. There may be an increased risk for the diagnosis of type 2 diabetes after COVID-19 infection due to a variety of different mechanisms.
As for people with type 1 diabetes, we also don’t know if having a COVID-19 infection increases their risk. We do know that there was an increase in the severity of diabetic ketoacidosis presentation during the pandemic, so we need to be sure that we reinforce sick-day rules with our patients with type 1 diabetes and that all individuals with type 1 diabetes have the ability to test their ketone levels at home.
In people with new-onset diabetes, whether type 1 or type 2, caused by COVID-19 or not, we need to treat appropriately based on their clinical situation.
Data from registries started during the pandemic will provide more definitive answers and help us find out if there is a relationship between having had COVID-19 infection and developing diabetes.
Perhaps that can help us better understand the mechanisms behind the development of diabetes overall.
Dr. Peters is professor of medicine at the University of Southern California, Los Angeles, and director of the USC clinical diabetes programs. She disclosed ties with Abbott Diabetes Care, AstraZeneca, Becton Dickinson, Boehringer Ingelheim Pharmaceuticals, Dexcom, Eli Lilly, Lexicon Pharmaceuticals, Livongo, MannKind Corporation, Medscape, Merck, Novo Nordisk, Omada Health, OptumHealth, Sanofi, and Zafgen. A version of this article first appeared on Medscape.com.