How COVID-19 disrupts glycometabolic control.

Coronavirus disease 2019 (COVID-19) is associated with hyperglycaemia. A study published in Nature Metabolism now shows how hyperglycaemia develops in a cohort of 551 patients hospitalized with COVID-19 in Italy.

“We started from a clinical observation: in patients hospitalized for COVID-19, there is a huge rate of new-onset hyperglycaemia,” explains corresponding author Paolo Fiorina. “In these patients, clinical outcomes are the poorest, with more requirement for ventilation, need of ICU and longer length of hospitalization.” Of note, these patients did not have pre-existing diabetes mellitus, as their levels of HbA1c were normal.

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In patients with new-onset hyperglycaemia at hospital admission for COVID-19, persistent hyperglycaemia (6 months) was observed in 35%, diabetes mellitus was diagnosed in ∼2% and the remaining patients became normoglycaemic. Continuous glucose monitoring was used in a small number of patients with COVID-19 to confirm the impaired glycaemic profile. Importantly, this approach showed some glycaemic alterations also persisted in some of those who had recovered from COVID-19.

The serum hormone profile (tested under fasting conditions and arginine stimulation) was altered in patients with COVID-19 and patients who had recovered from COVID-19. These changes demonstrated persistent insulin resistance and suggested that β-cell hyperstimulation might be occurring in COVID-19.

Patients with COVID-19 also showed changes in the cytokine secretome

Patients with COVID-19 also showed changes in the cytokine secretome, which persisted long after recovery. Of note, using tocilizumab (anti-IL-6) to treat patients with COVID-19, new-onset hyperglycaemia and high levels of IL-6 reduced glycaemia. This preliminary finding suggests a mechanistic link between disrupted cytokines and glycaemia in COVID-19. “Our data demonstrate that COVID-19 is associated with aberrant glycometabolic control, which can persist even after recovery,” concludes Fiorina. “These data suggest that further investigation of metabolic abnormalities in the context of long COVID is warranted.”