Since the start of the coronavirus pandemic, health officials have cautioned that people with diabetes are at increased risk of developing severe symptoms of COVID-19.
Researchers analyzed data from 1,317 COVID-19 patients with diabetes who were hospitalized at 53 public and private French hospitals during a three-week period in March. The average age of the patients was 70, and two-thirds of them were men. Most — 89 percent — had type 2 diabetes, a type of diabetes associated with aging and being overweight.
The researchers looked to see how COVID-19 affected the patients’ medical outcomes. They found that by day seven of their hospitalization, 29 percent of the patients with diabetes had died or been put on a ventilator to breathe. More specifically, one in 10 had died, and one in five were on a ventilator. Only 18 percent were discharged within a week of being hospitalized.
Those are troubling findings. Diabetes, particularly type 2 diabetes, is a major health issue in the United States, affecting 34 million people — about one in 10 of all Americans. By the way, for comparison, France has about 3.3 million people with diabetes, or about one in 20 of its population.
Poor blood sugar control was not associated with poorer outcomes in the study, but having diabetic complications more than doubled the risk of dying by the seventh day of hospitalization. That was true of both microvascular complications (which involve the eyes, nerves and kidneys, and are caused by damage to the small blood vessels) and macrovascular complications (which include cardiovascular diseases, such as heart disease and stroke, and are caused by damage to larger blood vessels).
Older age was associated with an increased risk of death among the patients with diabetes. Those who were aged 75 or older were 14 times more likely to die of COVID-19 after being hospitalized than those under the age of 55, and those aged 65 to 74 were three times more likely.
Having the respiratory condition obstructive sleep apnea almost tripled the risk of dying within the first week of hospitalization for the patients with diabetes, as did having a history of shortness of breath.
A higher body mass index (BMI) also independently raised the risk for a more severe outcome, particularly the need for a ventilator. Interestingly, however, the researchers noted an “obesity paradox” — a finding that people who had morbid obesity appeared to be less likely to require ventilation than those who were overweight or who had lower classes of obesity.
One finding from the study should be reassuring for people with diabetes. Using insulin to keep blood sugar levels in control — indeed, all treatments for modifying blood sugar — was not found to be a risk factor for more severe symptoms of COVID-19. The researchers stressed that people with diabetes should continue with their treatments.
Limitations and implications
The study looked only at people with diabetes who were hospitalized. Its results, therefore cannot be generalized to all people with diabetes and COVID-19, particularly those with less severe coronavirus infections. In addition, the study focused only on the patients’ short-term prognosis (seven days after hospitalization). Its findings may not reflect long-term outcomes.
Still, as the study’s authors point out, several epidemiological studies have identified diabetes as one of the major underlying medical conditions affecting the severity of COVID-19.
“It is well known that people with diabetes have increased infection risk, especially for influenza and pneumonia,” they add. “Moreover, diabetes was previously reported as a major risk factor for mortality in people infected with the 2009 H1N1 pandemic influenza and, more recently, with the Middle East respiratory syndrome-related coronavirus (MERS).”