Can Covid-19 cause diabetes and heart complications?

As the world continues to fight the novel coronavirus, the number of Covid-19 deaths has approached three million globally. From the near 78 million recoveries, research is beginning to make clear the severe symptoms and side effects that have emerged after contracting the virus.

Reports from more than 350 clinicians are now raising questions over whether Covid-19 can cause both type 1 and type 2 diabetes in patients who recovered from the virus.

Professor Francesco Rubino, a clinician at King’s College London, has called for a full investigation into the possible relation between Covid-19 and diabetes.

Rubino and his colleagues exchanged the anecdotal cases over a Zoom meeting, and then started to analyse diabetes cases that emerged after contracting Covid-19.

“Over the last few months, we’ve seen more cases of patients that had either developed diabetes during the Covid-19 experience, or shortly after that. We are now starting to think the link is probably true – there is an ability of the virus to cause malfunctioning of sugar metabolism,” said Rubino.

Some doctors also believe Covid-19 could induce a new form of diabetes by disrupting all sugar metabolism of the human body.

In America, over eight studies involving more than 3,700 Covid patients who have recovered post illness, showed that nearly 14 percent of patients went on to develop diabetes.

Other recent studies have suggested a similar relationship. For example, 2.35 percent of coronavirus patients in China developed new-onset diabetes six months after they were discharged.

Besides a causal link, a high proportion of people who are in intensive care units with Covid-19 also have diabetes. 

It has rapidly become a major disease around the world, with the risk of dying early only increasing.

"The number of people with diabetes has quadrupled in the last 40 years. It is the only major noncommunicable disease for which the risk of dying early is going up rather than down,"  said the World Health Organization’s Director-General, Tedros Ghebreyesus.

Does Covid-19 cause cardiac disease?

An increasing number of studies suggest that many Covid-19 survivors have developed some type of heart damage, “even if they didn't have underlying heart disease and weren't sick enough to be hospitalised,” according to the American Heart Association.

"Very early into the pandemic, it was clear that many patients who were hospitalized were showing evidence of cardiac injury," said Dr. Gregg Fonarow, chief of the division of cardiology at the University of California, Los Angeles.

The complications like myocarditis and inflammation of the heart muscle could go on to cause heart failure.

"More recently, there is recognition that even some of those Covid-19 patients not hospitalised are experiencing cardiac injury. This raises concerns that there may be individuals who get through the initial infection, but are left with cardiovascular damage and complications," Fonarow added.

Furthermore, those with pre-existing heart disease who don't have Covid-19 but are afraid to visit hospital out of fear of being exposed to the virus, are at further risk of heart failure.

According to research carried out in Germany, 100 patients who were thought to have recovered from Covid-19 were examined based on a negative nasal swab.

Two to three months after their diagnosis, 60 of the individuals had indications of myocardial inflammation. 

“Three individuals with severe abnormalities underwent biopsies that confirmed active inflammation in their heart muscle tissue,” the study found.

Whether cardiovascular damage is common or not in Covid-19 patients remains unclear.