By now, it’s well understood that people with diabetes are at higher risk for poor outcomes related to COVID-19 if they develop the viral infection — including the risks for hospitalization, admission to the intensive care unit (ICU), and death. Studies have also shown that people with diabetes who have higher blood glucose levels — both before admission to the hospital and during their hospital stay — are at higher risk for death from COVID-19.
But high blood glucose levels aren’t the only pattern of blood glucose control that can cause problems. Low blood glucose (hypoglycemia) can pose an immediate, serious health risk if it’s severe enough. On top of that, past studies have shown that people with diabetes who have greater volatility in their blood glucose levels — more ups and downs — may be at higher risk for certain poor outcomes, such as coronary artery disease (CAD).
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So it makes sense that researchers would be interested in looking for a connection between blood glucose fluctuation and the risk of death in people hospitalized with COVID-19, which was the focus of a newly published study.
Early glucose fluctuations linked to death risk
The study, published in the journal Diabetes Care, included 548 people hospitalized for COVID-19 — 99 of them with diabetes — in the Central Hospital of Wuhan, China, between January 2 and February 15, 2020. Researchers looked at patients’ medical records to determine their daily fasting blood glucose levels during the first week of their hospital stay, then calculated how much a person’s glucose levels fluctuated during this week. They compared this fluctuation with whether a patient was discharged from the hospital or died.
Overall, 489 patients were discharged, while 59 died. Not surprisingly, in line with what other studies have found, patients with a higher overall average glucose level during their first week in the hospital were at higher risk for a range of poor outcomes — including severe pneumonia, acute respiratory distress syndrome (ARDS) and death. But regardless of a person’s average overall glucose level, fluctuation in glucose levels over the week was tied to a higher risk of death. Compared with the quartile (one-fourth) of patients with the lowest level of glucose fluctuation, the quartile with the highest level of fluctuation was 1.97 times as likely to develop ARDS during their hospital stay, and 2.73 times as likely to die.
Of course, the hospitalizations in this study happened very early in the COVID-19 pandemic, before the connection between glucose levels and outcomes related to COVID-19 had been studied in any meaningful way. There were no established protocols for how to monitor or control blood glucose in people hospitalized for the viral infection, so it’s unknown whether the fluctuation found in the study could have been prevented with more intensive glucose control in the hospital.
But it’s still useful to know that glucose fluctuation during the first week of a patient’s hospital stay — before many poor outcomes like ARDS or death occurred — were linked to these outcomes, showing the need to adopt blood glucose monitoring and controlling protocols as soon as someone is hospitalized.
More monitoring tools due to COVID-19
Many hospitals in the United States have changed their protocols for monitoring patients’ blood glucose levels during the COVID-19 pandemic, adopting continuous glucose monitoring (CGM) systems that were previously not approved for use in hospitals. Before this, the standard practice was to regularly draw blood from patients and perform lab glucose test — the gold standard for accuracy. But for patients with COVID-19, it became clear that there was a need for more frequent glucose monitoring than hospital staff could keep up with — as well as a need to limit unnecessary interaction with infected patients. This led to the U.S. Food and Drug Administration (FDA) expanding the designation of CGM systems to include hospital use during the current pandemic.
So it’s not clear that the current study will yield any meaningful changes to hospital protocols, or even that it should prompt any changes, given how much attention is already being paid to glucose levels in COVID-19 patients. Still, the study demonstrates just how critical it is to control blood glucose levels early and attentively in people hospitalized with the infection.
Want to learn more about coronavirus and diabetes? Read our latest COVID-19 updates.