It has been observed that patients have developed diabetes either while infected with coronavirus, or shortly after recovering from it.
A recent study presented at the annual meeting of the European Association for the Study of Diabetes 2021 by Prof Shuibing Chen at Weill Cornell Medicine in New York suggested that lung, colon, heart, liver, and pancreatic organoids could all be infected by COVID.
Insulin-producing beta cells within the pancreas were susceptible, and once infected by COVID, these cells produced less insulin, as well as hormones usually manufactured by different pancreatic cells, a phenomenon known as transdifferentiation.
Some of these findings may explain why some previously healthy people develop diabetes after catching the virus.
The relationship between COVID-19 and diabetes mellitus is complicated and bidirectional. On the one hand, diabetes mellitus is considered one of the most important risk factors for a severe course of COVID-19.
Several factors that are often present in diabetes mellitus are likely to contribute to this risk, such as older age, a proinflammatory and hypercoagulable state, hyperglycaemia (high sugar levels) and underlying comorbidities (hypertension, cardiovascular disease, chronic kidney disease and obesity).
On the other hand, a severe COVID-19 infection, and its treatment with steroids, can have a specific negative impact on diabetes itself, leading to worsening of hyperglycemia through increased insulin resistance and reduced beta-cell secretory function. Worsening hyperglycaemia can, in turn, adversely affect the course of COVID-19.