The longer the COVID-19 pandemic goes on, the more physicians who treat diabetes are learning about how it affects their patients. Last year we reported on how the diabetes drug metformin might lower the risk of death from the COVID virus in patients with type 2 diabetes, how glucagon-like peptide 1 (GLP-1) receptor agonist diabetes drugs and SGLT2 inhibitors might have a role to play in fighting COVID, how the COVID virus might actually cause the development of type 1 diabetes in certain patients, and how the COVID vaccine will work just as well in diabetes patients as in those without diabetes.
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Now a recent study from researchers in China reports that adults with COVID who also have a high HbA1c are at greater risk for respiratory distress and a higher likelihood of death. The hemoglobin A1C test, better known as the HbA1c test, has been a useful tool in the diagnosis and treatment of diabetes for over 40 years. Unlike the familiar daily finger-prick blood sugar test that people with diabetes know well, which tells you your blood sugar level right now, the HbA1c test is especially valuable because it measures blood sugar over time — the two- to three-month period preceding the test. The study was published in the Journal of Diabetes Investigation.
The research team was led by Benping Zhang, MD, of the department of endocrinology at Tongji Hospital in Wuhan, China, where the COVID-19 virus was first identified. According to Zhang, “For the first time, we explored the effects of blood glucose on complications, severity and mortality rate of COVID-19 patients from the perspective of HbA1c, which reflects the long-term glycemic control degree before admission.”
The researchers studied 77 patients who had been admitted to and treated in intensive care wards at Tongji Hospital. The average age of the patients was 63.6 and 62% were men. Forty were rated severely ill and the rest critically ill. The ones who were not discharged died in the hospital.
The researchers divided the patients according to their HbA1c levels. Forty-nine had an HbA1c of less than 6.5% and 28 had levels above 6.5% (an HbA1c level between 5.7% and less than 6.5% is considered to be in the prediabetes range and 6.5% or higher is in the diabetes range). The researchers also determined that five people in the lower HbA1c group had diabetes and every patient in the higher group had diabetes. In addition, they also found that patients in the higher group had higher pulse rates, a higher white cell count, and lower percutaneous oxygen saturation. (Percutaneous oxygen saturation is a measurement of the percentage of hemoglobin in the blood that is saturated with oxygen. Too low a level might require therapy.)
Most important in terms of COVID-19, it was found that patients in the higher HbA1c group were more likely to develop secondary respiratory infection (89%, as compared to 67% in the lower HbA1c group). Also, 61%of the higher HbA1c group developed acute respiratory distress syndrome, but only 29% of the lower HbA1c group did. Sixty-eight percent of the higher group were rated critically ill; just 37% of the lower group was similarly ranked. Finally, 46% of the higher group died, while 22% of the lower HbA1c group died. The researchers adjusted their findings to take into account the age and sex of the patients, as well as other illnesses they had, and still found the risks to be greater in the high HbA1c group. As the researchers wrote, “The incidence of critically ill cases and mortality rate were significantly higher in the insufficient glycemic control group, and HbA1c was a significant independent risk factor associated with in-hospital death of patients with COVID-19.”
The findings point to one clear conclusion: Patients with high HbA1c levels need to be closely watched for respiratory infections, and vice versa. As the researchers expressed it, “Routine examination of HbA1c and timely identification and treatment of pulmonary secondary respiratory infections and acute respiratory distress syndrome might be beneficial to improve the prognosis of COVID-19 patients with insufficient glycemic control.”
Want to learn more about coronavirus and diabetes? Read our latest COVID-19 updates.