One fact that has been clear almost since the start of the COVID-19 pandemic in the United States is that people with diabetes are at especially high risk for poor outcomes if they develop the viral disease. Having diabetes puts you at greater risk for needing hospitalization, and for worse outcomes once you’re in the hospital, including lingering complications and a higher risk of death.
But not all people with diabetes are at the same risk for worse outcomes if they develop COVID-19. Several studies have shown that better blood glucose control — both before and during hospitalization — reduces the risk of poor outcomes, including death, in people who develop the infection.
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A recent study looked at one group of people with diabetes in particular: those who experience a complication called diabetic retinopathy (eye disease). Based on the results, this group appears to have worse outcomes related to COVID-19 than other people with diabetes.
Greater risk of needing assistance to breathe
The new study, published in the journal Diabetes Research and Clinical Practice, looked at one of the most feared outcomes related to COVID-19: needing to be intubated in order to breathe.
The study examined a group of 187 people with diabetes — 179 people with type 2 diabetes, and 8 with type 1 diabetes — with an average age of 68, who were hospitalized with COVID-19 at a single hospital in Britain during a roughly four-week period in the spring of 2020. Because all study participants received care through Britain’s National Health Service (NHS), data on diabetes complications for these patients was readily available in their medical files. Researchers looked at both diabetic retinopathy and chronic kidney disease, and how having these conditions corresponded to outcomes related to their hospitalization for COVID-19.
Among all participants, 67 (36%) had diabetic retinopathy. Out of those with retinopathy, 52 (80%) had less severe background retinopathy, while 15 (20%) had more advanced retinopathy based on recent eye screening.
During their hospital stay for COVID-19, 49 patients (26%) were intubated due to difficulty breathing, and 60 patients (32%) died. Surprisingly, being older, having diabetes for a longer duration, and having chronic kidney disease were all associated with a lower risk of intubation. But having retinopathy and being obese were associated with a higher risk of intubation — with an intubation risk about five times higher in people with diabetic retinopathy. There was no increased risk of death associated with retinopathy.
Marker of blood vessel damage
As the researchers write in a discussion of their findings, this study doesn’t prove that diabetic retinopathy directly leads to a higher risk of intubation. And to most people, it’s not logical to suspect that having an eye problem makes it more difficult to breathe, requiring intubation.
Instead, the researchers note, having retinopathy probably means that you have blood vessel damage in other areas of your body, caused by elevated blood glucose levels over time. This damage may be present in your lungs, or in other areas of the body that COVID-19 attacks, leading to breathing problems in people with a severe enough infection to require hospitalization.
While this is a fairly small study, it’s based on very complete data on diabetic retinopathy for its participants, a benefit that may not apply to many larger studies on COVID-19 outcomes. So while it’s not enough to cause sweeping recommendations, it does suggest that when looking at people with diabetes who are hospitalized with COVID-19, diabetic retinopathy may be an indication of who is likely to require breathing assistance. These results may also help guide research going forward on how diabetes is related to worse outcomes in people who develop COVID-19.
Want to learn more about coronavirus and diabetes? Read “Coronavirus and Diabetes: A COVID-19 Update,” “Healthy Eating During Hard Times” and “COVID-19: Staying Safe at Work.”
