Since the beginning of the COVID-19 pandemic, there has been little good news about the relationship between diabetes and outcomes related to the viral infection. People with diabetes — both type 1 and type 2 — face a higher risk of hospitalization, admission to the intensive care unit (ICU) and death if they develop COVID-19, especially if they have a history of less than optimal blood glucose control. This higher risk of poor outcomes means that people with diabetes should be vigilant about precautions to help prevent COVID-19, including getting vaccinated when possible.
A new study makes clear just how dire the risk of death is for people with diabetes who are hospitalized with COVID-19, and also identifies several factors linked to this death risk. Not surprisingly, these factors tend to indicate more advanced or poorly controlled diabetes, along with having more cardiovascular risk factors.
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Microvascular complications raise death risk
The study, published in the journal Diabetologia, found that in a nationwide study of people with diabetes who were hospitalized with COVID-19 in France, the overall rate of death within 28 days was 20.6% — a shocking number, even though the risk of death linked to diabetes has been known for a long time. Researchers were interested in figuring out which factors made death within 28 days more likely, as well as those that made a discharge from the hospital more likely within the same timeframe.
Out of 2,796 participants in the study who had diabetes and were hospitalized with COVID-19, 50.2% were discharged from the hospital within 28 days, while 20.6% died and the rest remained hospitalized. Among those who were discharged, the median hospital stay was nine days. A younger age, taking metformin before hospitalization, and having COVID-19 symptoms for a longer period of time before hospitalization were all linked to a greater chance of being discharged within 28 days.
Among all study participants, 44.2% had microvascular diabetic complications (those affecting small blood vessels, such as in the eyes or kidneys) while 38.6% had macrovascular complications (those affecting large blood vessels, including coronary arteries and peripheral arteries). The researchers found that a history of microvascular complications, taking anticoagulant drugs before hospitalization, having difficulty breathing (dyspnea) at the time of hospital admission, and having higher C-reactive protein (a blood marker of inflammation) were linked to a smaller chance of of being discharged within 28 days.
The researchers found that the factors linked to a smaller chance of being discharged were also linked to a greater risk of death. Additional factors linked to a higher risk of death included taking insulin or statins (lipid-lowering drugs) before hospitalization. Needless to say, this doesn’t mean taking insulin or statins was responsible for the higher risk of death linked to them — instead, people who took these medications most likely had more advanced diabetes and additional cardiovascular risk factors compared with those who didn’t take them.
Inconsistencies compared with other studies
One unusual finding of this study was that it didn’t find a link between A1C (a measure of long-term blood glucose control) at the time of admission to the hospital and the risk of either discharge or death within 28 days, as noted in a news release from Diabetologia. This is notably different from what other studies have found, namely that blood glucose control both at the time of hospital admission and during a person’s hospital stay are linked to the risk of certain outcomes, including death.
On the other hand, this study did find that a higher actual blood glucose level at the time of hospital admission strongly predicted a higher risk of death, and a lower risk of discharge, within 28 days. So it’s possible that in people with diabetes, those who develop severe COVID-19 may experience a spike in blood glucose even if they previously had fairly good blood glucose control.
Overall, the results of this study aren’t helpful to individual people with diabetes as much as they may be to healthcare workers in hospitals, who are trying to decide how to prioritize and manage treatment for people with COVID-19. “The identification of favorable variables associated with hospital discharge and unfavorable variables associated with death can lead to patient reclassification and help to use resources adequately according to individual patient profile,” the researchers wrote.
Want to learn more about coronavirus and diabetes? Read our latest COVID-19 updates.