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How Does COVID-19 Affect People with Diabetes?

COVID can cause severe illness, but risk is lower if diabetes in check

A woman with diabetes pricks her finger to test her blood sugar.

COVID can cause severe illness, but risk is lower if diabetes in check

As the pandemic lingers on, it’s become apparent that some populations have been hit harder than others. People with diabetes, along with the elderly, are among those at the top of the list. 


It’s estimated that 30 to 40 percent of all coronavirus deaths in the US have been people with diabetes. 


More than 30 million Americans are living with diabetes. 


An estimated 5 to 10 percent have type 1, an autoimmune condition that prevents the pancreas from making insulin, a hormone that triggers cells to absorb and use the glucose derived from foods we eat. 


The vast majority have type 2, meaning their bodies produce insulin but cannot use it efficiently. Instead of being used for energy, glucose stays in the blood, which can cause serious health problems over time. 

Why is COVID riskier for people with diabetes?

“COVID seems to have a dramatic effect on stimulating cytokines, which are inflammatory factors. That makes insulin resistance worse and can elevate blood sugars,” says Athena Philis-Tsimikas, MD, an endocrinologist at Scripps Clinic, and medical director at the Scripps Whittier Diabetes Institute


“High blood sugars also lower the ability of white blood cells to fight infections, therefore, again, putting you at higher risk for a worse outcome.” 

Why is COVID riskier for people with obesity?

Not only does diabetes increase the likelihood of severe complications from COVID, but the comorbidities that often come with it can worsen the infection.


Laura Nicholson, MD, PhD, an internist and hospitalist who cares for hospital patients with COVID and diabetes, and her team studied the effects of COVID on people with one of the most common comorbidities and risk factors for diabetes: obesity. 


They looked at the role obesity played in people treated in intensive care, needing a ventilator and dying in the hospital. During the initial COVID surge (before vaccines were available), obese people were at increased risk for all three things. 


“The risk gets higher as the weight goes up,” Dr. Nicholson says. However, the issue is complex because obesity also often presents with its own set of comorbidities, one of which is diabetes.”


“It’s difficult to separate the effects of obesity, which affects breathing, and the effects of everything else that obesity causes — hypertension, diabetes, all of the downstream diseases, if you will — that increase the risk of dying of an infection,” she says. 


Not everyone who is obese will develop type 2 diabetes and its related health problems, though obesity and inactivity are the most common triggers for the disease because the pancreas can produce only so much insulin, which can become insufficient as the body grows larger. Genetics and many other contributing factors also play a role in why some people develop diabetes and other don’t. 

How is diabetes managed?

Diabetes can be controlled with insulin injections or medication that prompt the pancreas to ramp up insulin production. A healthy diet and exercise, as well as interventional programs, such as those offered at the Scripps Whittier Diabetes Institute, can also go a long way toward managing diabetes or even stopping it from developing. 


Dr. Philis-Tsimikas notes that people with well-controlled diabetes don’t face the same complications when it comes to COVID. 


“If you have someone that is very well-managed, whether they have type 1 or type 2 diabetes, they don’t have complications,” she says. “The key to all of this is that well-managed diabetes doesn’t result in as many bad outcomes or worse outcomes, whereas poorly managed diabetes does.” 

How does COVID-19 vaccine help?

To prevent COVID or minimize its symptoms, getting vaccinated and keeping up to date with boosters is the best line of defense, says Dr. Nicholson. 


“Obese people and elderly people do much better with COVID if they’ve been immunized,” Dr. Nicholson says. “We can still bring you up to a much better immunity. Now something will be a bad cold instead of a very serious pneumonia.” 

The cover of the September 2022 issue of San Diego Health Magazine.

This content appeared in San Diego Health, a publication in partnership between Scripps and San Diego Magazine that celebrates the healthy spirit of San Diego.