Recent research suggests that the coronavirus may trigger huge increases in the diabetic population especially in severe cases.
In which case, diabetic patients must monitor their blood sugar levels.
In August 2020, scientists from Imperial College London warned the infection can cause type 1 diabetes in children, with new incidences doubling amid the pandemic.
Published in the journal Nature Metabolism, the new study has revealed that 46 percent of the 551 patients admitted to an Italian hospital with coronavirus complications developed high blood sugar levels, a common problem among people with diabetes.
These abnormalities persisted "for at least two months in [the] patients who recovered from COVID-19 [the disease caused by the coronavirus]."
With medics unsure how best to treat coronavirus-induced diabetes, one expert has warned "we may see a huge increase in the diabetic population."
UK diabetes situation
In the UK, 3.9 million people had been diagnosed with diabetes in 2019, of whom around 90% had type 2.
Type 2 diabetes' onset is often linked to a patient's lifestyle, which may include carrying excess weight or being too sedentary.
Conversely, type 1 diabetes is an autoimmune disease that occurs when a patient's body mistakenly attacks insulin-producing cells. Insulin is a hormone that helps the body use sugar for energy, lowering levels in the blood.
People with diabetes are known to be more at risk of severe ill health with the coronavirus itself, with research increasingly suggesting the latter can also trigger the disease.
To better understand the emergence of diabetes amid the pandemic, scientists from the Boston Children's Hospital analyzed 551 people who were admitted to a Milan hospital between March and May, 2020.
The patients were fitted with a sugar sensor upon admission and followed for up six months.
"These people were not diabetic before, but during admission, about 46% of the patients were found to have new hyperglycemia," said lead author Dr Paolo Fiorina.
Hyperglycemia is the medical term for high blood sugar levels. Over time, it can cause permanent damage to a patient's eyes, nerves, kidneys or blood vessels.
A sudden spike in blood sugar levels may trigger diabetic ketoacidosis – when the body breaks down fat for energy, which can lead to a coma – or a hyperosmolar hyperglycemic state – severe dehydration as the body tries to rid excess sugar.
The hyperglycemia patients also fared worse than those with normal glucose levels – including a longer hospital stay, more severe symptoms, and a higher need for oxygen, ventilation or intensive care.
Perhaps surprisingly, these patients were also found to be "severely hyperinsulinemic – they produced too much insulin", according to Dr Fiorina.
In addition, the hyperglycemia patients produced abnormal levels of an insulin precursor and impaired islet beta cells, which make and secrete the blood sugar-lowering hormone.
"Basically, the hormonal profile suggests that the endocrine pancreatic function is abnormal in those patients with COVID-19 and it persists long after recovery," said Dr Fiorina. Insulin is made in the pancreas.
Direct effect of COVID in pancreas
Coronavirus complications have long been linked to a patient's immune system over-reacting to the infection, leading to a cascade of inflammatory molecules that mistakenly attack healthy tissue.
The Boston scientists found blocking inflammatory immune proteins called cytokines improved the patients' blood sugar levels.
Other issues remained, however, with many of the patients enduring abnormally elevated glucose levels after eating.
"This study is one of the first to show that COVID-19 has a direct effect on the pancreas," said Dr Fiorina.
"It indicates the pancreas is another target of the virus affecting not only the acute phase during hospitalization, but potentially also the long-term health of these patients."
"If you keep targeting and blocking insulin, but you have a strong and chronic inflammation, it may lead to chronic damage," said Dr Fiorina, who is calling for larger studies to test potential therapies.
He added: "When you consider how many patients have been hospitalized with COVID-19, and continue to be worldwide, we may see a huge increase in the diabetic population."
Although it is unclear why this may occur, the pancreas can express high levels of the so-called ACE2 receptor, which the coronavirus uses to enter cells. The virus has also been identified in the pancreas of people who died with the infection.
Inflammation triggered by a coronavirus patient's immune system may also damage the organ, affecting its ability to produce insulin.
Diabetic patients die with COVID infection
Another study published in India showed that 1 in 5 hospitalized Covid-19 patients with diabetes as co-morbidity likely dies after getting infected.
The French CORONADO study, published in the government journal Clinical Trials, had begun during the first wave of the pandemic in early 2020.
The study’s preliminary investigation had found that 10.6 per cent of patients with type 2 diabetes and Covid-19 and 5.6 per cent of those with type 1 diabetes and Covid-19 died within a week after hospitalization.
The researchers carried out further investigation, which was published in the journal Diabetologia, by involving 2796 Covid-19 patients with diabetes who were hospitalized at 68 institutions across France between March 10 and April 10, 2020, and followed for 28 days.
The researchers observed that the primary outcome was tracheal intubation and/or death.
“We put together all the relevant medical information: history, usual treatment, clinical and biological presentation, and hospital prognosis,” says lead author Matthieu Wargny, MD, L’Institut du Thorax, INSERM, CNRS, University Hospital of Nantes, France.
“We were also interested in positive outcomes, like returning home or to a care home, transfer to another hospital, or follow-up care,” Wargny noted.
The study revealed that after 28 days, 577 patients (20.6 per cent) had died and 1404 (50.2 per cent) had been discharged. The median duration of hospital stay was 9 days.
Wargny added: “We also found that 12.2 per cent of patients were still in hospital and 16.9 percent had been transferred.”
The researchers further noted that this may vary according to the prevalence of the virus in the current situation.
He added that the researchers “were able to identify the principal prognostic risk factors, both negative and positive.”
Among the risk factors that led to poorer outcomes, advancing age was the most important. This was followed by a history of microvascular complications, particularly kidney and eye damage, dyspnea on admission, and inflammatory markers (white blood cell count, raised C-reactive protein, and elevated aspartate transaminase).
Among the positive risk factors, researchers identified routine treatment with metformin and a history of Covid-19 symptoms before hospitalization.