Type 2 diabetes

COVID-19 patients have extremely high insulin requirements

People with type 2 diabetes who become critically ill with COVID-19 disease need extremely high amounts of insulin to maintain glycaemic control at the height of their illness, Australian clinicians have reported.

A case series of eight COVID-19 patients with T2D admitted to ICU for ventilation at Sydney’s Westmead Hospital found that their insulin requirements peaked at more than 200 units per day, although most later improved and were treated with subcutaneous insulin and oral hypoglycaemic drugs on discharge.

The report published in Clinical Endocrinology, covered eight patients with a mean age of 55 of whom three were newly diagnosed with T2D on admission. Their mean HbA1c was 9.2% (77 mmol/mol) and all had c-peptide levels and negative anti-GAD antibodies were found consistent with T2D.

During ICU treatment the patients’ insulin requirements increased alongside c-reactive protein (CRP) levels to a mean peak of 201 units per day. The median glucose level on insulin infusion was 9.5 mmol/L, and 54% of glucose levels in target (4-9.9 mmol/L).

Once off insulin infusion, seven of the eight patients required subcutaneous insulin. Median glucose level was 8.0 mmol/L off infusion, with 72% of glucose levels in target. Six of the eight patients have been discharged, all of whom required oral hypoglycaemic agents and four required insulin (18±10.9 units).

Dr Linda Wu and co-authors of the report from Westmead’s Department of Diabetes & Endocrinology said the CIOVID-19 patients’ insulin requirements were much higher than those seen in other studies of people with diabetes admitted to ICU, some of which had reported a mean daily insulin dose of only 34 units per day to achieve a glucose target of around 6-10 mmol/L.

They said it was not known whether the high insulin requirement was due to profound insulin resistance from severe systemic illness or insulin deficiency direct islet injury caused by the SARS-COV2 virus.

One hypothesis is that SARS-COV2 could lead to islet inflammation and beta cell stunning because it binds to ACE2 receptors for cell entry and ACE2 receptors are expressed in the pancreas, they noted.

“On the basis of these findings, it is now established practice at our centre to screen all patients with COVID-19 for diabetes with HbA1c and plasma glucose. Tight glycemic control is sought, using insulin infusions when critically unwell and transitioning to subcutaneous insulin when off enteral nutrition,” they wrote.

“Oral hypoglycaemic agents with low risk profile are gradually introduced as oral intake stabilises. Follow up will elucidate whether these patients have an ongoing need for insulin which might suggest long-term islet cell damage.”

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