A major review of studies from the first 18 months of the COVID-19 pandemic, published in the journal Diabetes Care, shows the central role diabetes has played in the widespread damage caused by the viral infection.
From almost the beginning of the pandemic, it has been clear that people with diabetes are at higher risk for severe outcomes related to COVID-19, including hospitalization, admission the the intensive care unit (ICU), and death. But the full extent, so far, of how diabetes has affected the course of the pandemic is now being assessed in greater detail by researchers — and it has become clear that diabetes is a key reason why the toll of the pandemic has been so great. On the other side of the coin, people with diabetes have been greatly and disproportionately affected by the pandemic, and this burden has been made clear by recent assessments.
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Pandemic disproportionately affecting people with diabetes
For the latest review, researchers looked at how diabetes is related to COVID-19 outcomes, what factors predict the worst outcomes in people with diabetes, and what course the pandemic has taken due to diabetes — as well as the course it is likely to take going forward. They noted that based on the latest available data, people with type 1 or type 2 diabetes account for 30% to 40% of all COVID-19 hospitalizations. What’s more, among hospitalized patients with diabetes, 21% to 43% require intensive care, and the fatality rate is about 25%. Overall, the risk for severe disease or death due to COVID-19 is 100% to 250% higher in people with diabetes than in people without diabetes.
It’s true, though, that some people with diabetes who were hospitalized with COVID-19 and died during the pandemic would have died during the same time period even without COVID-19 — just as this is true for people without diabetes. So the researchers assessed how COVID-19 has affected the overall risk of death for people without diabetes, as well as for people without diabetes. They found that compared with historical trends, the overall rate of death for people with diabetes has increased by about 50% over the course of the pandemic — more than twice the increase seen in the general population. So it’s not the case that COVID-19 is claiming only the sickest people who most likely would have died anyway. Instead, it’s disproportionally killing people with diabetes who would have otherwise survived, compared with people without diabetes who would have otherwise survived.
One especially troubling aspect of the excess deaths seen in people with diabetes since the start of the pandemic is that about 75% to 85% of these deaths are not officially listed as due to COVID-19. Researchers don’t know exactly why this is the case, but it may be because many people with diabetes developed asymptomatic COVID-19 and didn’t get tested and diagnosed with the infection — but still experienced worse outcomes due to the virus in the form of cardiovascular disease or kidney disease. It’s also possible that the pandemic has had a major effect on health-related behaviors, but there is likewise not much data to show whether or not this is the case. More research on potentially undiagnosed COVID-19 infections, as well as health behaviors in the wake of the pandemic, is needed to help shape the best response to minimize poor outcomes for people with diabetes going forward, the researchers wrote.
On the positive side, COVID-19 vaccination programs have served as a valuable “natural experiment” to monitor how COVID-19 affects populations with different levels of vaccination and diabetes differently. Most population-based studies have been done in the United States and the United Kingdom — good news for these populations, but potentially problematic when it comes to figuring out how vaccination and diabetes rates affect outcomes in other countries with very different COVID-19 exposures, health systems, and health-related behaviors.
One huge unanswered question is how COVID-19 affects people with diabetes who are not hospitalized, compared with people without diabetes who are not hospitalized. As “long COVID” — cases in which people have ongoing symptoms or disability following an initial infection — comes into greater focus, studies may show how having diabetes affects the duration and severity of both initial COVID-19 symptoms and any problems that linger or develop in the months that follow.
Want to learn more about coronavirus and diabetes? Read our latest COVID-19 updates.