While diabetes is known to be a risk factor for severe Covid outcomes, researchers are now observing a new long-term health concern in patients hospitalised with Covid-19 — an increase in new-onset hyperglycemia, or high levels of blood sugar lasting months after the infection.

Researchers from the Boston Children’s Hospital assessed the health of 551 people admitted to the hospital for Covid-19 in Italy from March through May 2020.

About half of the patients (46 per cent), with no history of diabetes, were found to have new hyperglycemia. A follow-up showed that while most cases were resolved, about 35 per cent of the newly hyperglycemic patients remained so at least six months after the infection, said the lead author of the study, Paolo Fiorina, from the Division of Nephrology at the hospital.

Compared to patients with no signs of glucose abnormalities, the hyperglycemic patients also had worse clinical concerns: longer hospitalisation, worse clinical symptoms, a higher need for oxygen, a higher need for ventilation, and an increased need for intensive care treatment.

The study was published in the journal Nature Metabolism. The team also found that hyperglycemic patients had abnormal hormonal levels.

“We discovered they were severely hyperinsulinemic; they produced too much insulin,” Fiorina said. They also had abnormal levels of pro-insulin, a precursor of insulin, and markers of impaired islet beta-cell function. Islet beta cells make and secrete insulin.

“Basically, the hormonal profile suggests that the endocrine pancreatic function is abnormal in those patients with Covid-19 and it persists long after recovery,” Fiorina added.

Hyperglycemic patients also had severe abnormalities in the number of inflammatory cytokines, including IL-6 and others.

While glucometabolic abnormalities declined over time in some patients — particularly after Covid-19 infection — other issues like higher post-prandial (after eating) glucose levels and abnormal pancreatic hormones remained in the post-Covid period.

“This study is one of the first to show that Covid-19 has a direct effect on the pancreas,” Fiorina said, adding, “It indicates that the pancreas is another target of the virus affecting not only the acute phase during hospitalisation but potentially also the long-term health of these patients.”

The study pointed to the importance of evaluating pancreatic function in patients hospitalised for Covid-19 — while in the hospital and over the long term.