By now, it’s well known to many people that having diabetes raises the risk of developing severe disease in people who get COVID-19. But researchers are continuing to study who, exactly, among people with diabetes is at the greatest risk — and the results tend not to be surprising. There is now growing evidence that having higher blood glucose levels contributes to worse outcomes in people with diabetes who develop COVID-19, as a recent study shows.
Published in the journal Diabetes Care, the study looked at the effects of “optimal glycemic control” in people with type 2 diabetes who were hospitalized for COVID-19, compared to those with higher blood glucose levels. The participants were 59 people admitted with moderate symptoms of COVID-19, all of whom had type 2 diabetes. Based on their blood glucose level at the time they were admitted to the hospital, participants were assigned to a “high” or “normal” category. During their hospital stay, all participants had their blood glucose monitored and controlled according to the hospital’s standard protocol.
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Researchers then looked at a number of different factors and outcomes in participants during their hospital stay, including two different blood markers: interleukin 6 (IL-6), which corresponds to inflammation due to infection, and D-dimer, which indicates blood vessel dysfunction. The researchers also took note of who developed severe COVID-19, was admitted to the hospital’s intensive care unit (ICU), required mechanical ventilation or died.
Out of the 59 participants, 34 fell into the “normal” blood glucose group, while 25 were in the “high” group based on initial blood glucose levels. In the “high” group, 60% required insulin infusion to control blood glucose levels during their hospital stay, while 40% did not. The average blood glucose level during hospitalization for those in the “high” group who received insulin was 138 mg/dl, while it was 192 mg/dl in those who weren’t given insulin. Levels of both IL-6 and D-dimer were higher at admission in the “high” group than in the “normal” group, and remained higher during the hospital stay even though both groups were receiving standard care for COVID-19.
The “high” group was also found to be at a greater risk for developing severe COVID-19 during their hospital stay. Within this group, those who received insulin were at lower risk for developing severe COVID-19 — which isn’t especially surprising, given that those who received insulin ended up with lower blood glucose levels during their hospital stay.
Taken together, these results show that higher blood glucose levels — both at the time of admission to the hospital, and during a hospital stay — can lead to worse outcomes in people with type 2 diabetes who are hospitalized for COVID-19. The researchers also write that “insulin infusion may be an effective method for achieving glycemic targets and improving outcomes in patients” with diabetes and COVID-19 — although it’s still unclear whether the protocol for giving insulin during hospitalization for COVID-19 should change due to these results. The risk of hypoglycemia (low blood glucose) might outweigh the benefits of lower blood glucose in people whose glucose levels aren’t deemed to be high enough to require insulin during their hospital stay, and more research would be needed to determine at what point the benefits of lower blood glucose outweigh the risks of hypoglycemia.
But for people with diabetes, this study makes a few things clear. Your risk of developing severe COVID-19 is lower if your blood glucose levels are in the normal range, but the risk of severe COVID-19 is also generally higher in all people with diabetes than in people without it. So in addition to making sure your blood glucose is controlled as well as possible, it makes sense to follow precautions to prevent COVID-19 — such as limiting unnecessary contact with other people, maintaining social distancing, wearing a mask in public, and washing your hands regularly and thoroughly.
Want to learn more about coronavirus and diabetes? Read “Coronavirus and Diabetes: What You Need to Know,” “Healthy Eating During Hard Times” and “Avoiding Coronavirus With Diabetes: Stock Up and Stay Home, CDC Says.”