Patients with high blood sugar at higher risk of COVID-19 complications

The COVID-19 causes severe disease in patients with underlying health conditions, such as diabetes, hypertension, severe lung disease, heart disease, and a weakened immune system.

Now, a team of researchers from the Union Hospital and Tongji Medical College, Huazhong University of Science and Technology in Wuhan City in China has found that COVID-19 patients with abnormally high blood sugar at an increased risk of severe complications and more than twice as likely to die.

Published in the journal Diabetologia, the study echoes previous studies about the link between high blood sugar and severe COVID-19 complications.

Elevated risk of mortality

Previous studies have tied hyperglycemia or abnormally high blood sugar and an elevated risk of death in community-acquired pneumonia (CAP), heart attacks, stroke, and other medical conditions. Amid the pandemic, deaths among those infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were highest in people who are older and those with chronic diseases.

Several studies have associated diabetes and poor outcomes in COVID-19 patients. However, scientists have not established the direct correlation between fasting blood glucose (FBG) level at admission to hospital and clinical outcomes of COVID-19 patients without a diagnosis of diabetes.

Study findings

To arrive at their findings, the team examined the relationship between FBG and 28-day mortality in coronavirus disease patients who are not previously diagnosed as having diabetes. They performed a retrospective study involving all consecutive COVID-19 patients admitted between January 24 and February 10 in two hospitals in Wuhan City.

The researchers analyzed clinical and demographic data, including 28-day outcomes, CEB-65 scores, and in-hospital complications. The CRB-65 score measures the severity of pneumonia based on four indicators, which include respiratory rate, level of confusion, systolic or diastolic blood pressure, and age.

A total of 605 COVID-19 patients were enrolled, including 114 patients who died in the hospital. Of the patients, 34 percent had one or more underlying conditions, with high blood pressure as the most common. About 29 percent were in the highest category of FBG of about 7.0 mmol/L on admission. Also, about 17 percent were in the range of prediabetes, and more than half had a normal FBG range.

The study results also showed that patients in the highest FBG group were about 2.3 times more likely to die than those in the lowest. Further, those with moderate levels of FBG or in the pre-diabetic group were 71 percent more likely to die than those in the lowest group.

“This study shows, for the first time, that elevated FBG (>7.0 mmol/l) at admission is independently associated with increased 28-day mortality and percentages of in-hospital complications in COVID-19 patients without a previous diagnosis of diabetes… we have also shown that FBG of 7.0 mmol/l or higher is associated with increased mortality, regardless of whether the patient has pneumonia that is more or less severe,” the team said.

Further, the data revealed that men had a 75 percent higher risk of dying from COVID-19 than women, and those with higher CBR-64 scores were more likely to die.

Potential mechanisms

The team also sheds light on the potential mechanisms for the increased death risk in those with diabetes, including clotting caused by hyperglycemia-induced changes in coagulation, altered function of the blood vessel walls, and the overproduction of inflammatory cytokines, also known as a cytokine storm.

Therefore, the team concluded that FBG higher than 7 mmol/L upon admission is an independent predictor for 28-day mortality in patients with COVID-19, even if they were not diagnosed with diabetes in the past. Hence, hospitals and clinicians should include blood sugar levels and glycemic testing to determine a patient’s risk of COVID-19 complications. Also, controlling blood sugar levels is essential to combat the novel coronavirus and prevent complications.  

The coronavirus pandemic has now killed more than 571,000 people and infected over 13 million people across the globe. The United States and Brazil are the hardest-hit countries, with 3.36 million and 1.88 million confirmed cases, respectively.